diff --git a/.DS_Store b/.DS_Store index f89600e9..f7ce0fd5 100644 Binary files a/.DS_Store and b/.DS_Store differ diff --git a/problems/0188.买卖股票的最佳时机IV.md b/problems/0188.买卖股票的最佳时机IV.md index def69277..0b1622ac 100644 --- a/problems/0188.买卖股票的最佳时机IV.md +++ b/problems/0188.买卖股票的最佳时机IV.md @@ -404,6 +404,47 @@ func max188(a, b int) int { } ``` +版本三：空间优化版本 + +```go +func maxProfit(k int, prices []int) int { + n := len(prices) + // k次交易，2 * k种状态 + // 状态从1开始计算，避免判断 + // 奇数时持有(保持或买入) + // 偶数时不持有(保持或卖出) + dp := make([][]int, 2) + dp[0] = make([]int, k * 2 + 1) + dp[1] = make([]int, k * 2 + 1) + + // 奇数状态时持有，i += 2 + for i := 1; i <= k * 2; i += 2 { + dp[0][i] = -prices[0] + } + + for i := 1; i < len(prices); i++ { + for j := 1; j <= k * 2; j++ { + if j % 2 == 1 { + dp[i % 2][j] = max(dp[(i - 1) % 2][j], dp[(i - 1) % 2][j - 1] - prices[i]) + } else { + dp[i % 2][j] = max(dp[(i - 1) % 2][j], dp[(i - 1) % 2][j - 1] + prices[i]) + } + } + } + + return dp[(n - 1) % 2][k * 2] +} + +func max(a, b int) int { + if a > b { + return a + } + return b +} +``` + + + ### JavaScript: ```javascript @@ -558,3 +599,4 @@ impl Solution { + diff --git a/problems/0309.最佳买卖股票时机含冷冻期.md b/problems/0309.最佳买卖股票时机含冷冻期.md index 95689a48..4913b8bd 100644 --- a/problems/0309.最佳买卖股票时机含冷冻期.md +++ b/problems/0309.最佳买卖股票时机含冷冻期.md @@ -357,6 +357,42 @@ func max(a, b int) int { } ``` +```go +// 一维优化版本 +// 时间复杂度O(n), 空间复杂度O(1) +func maxProfit(prices []int) int { + + // 0: 持有，一直持有和买入 + // 1: 不持有，一直不持有（不包含前一天卖出,因为这样的一天是冷静期，状态有区别） + // 2：不持有，今天卖出 + // 3：冷静期，前一天卖出（一直不持有） + dp0, dp1, dp2, dp3 := -prices[0], 0, 0, 0 + + n := len(prices) + + for i := 1; i < n; i++ { + t0 := max(dp0, max(dp1, dp3)-prices[i]) + t1 := max(dp1, dp3) + t2 := dp0 + prices[i] + t3 := dp2 + + // 更新 + dp0, dp1, dp2, dp3 = t0, t1, t2, t3 + } + + return max(dp1, max(dp2, dp3)) +} + +func max(a, b int) int { + if a > b { + return a + } + return b +} +``` + + + ### Javascript: > 不同的状态定义 感觉更容易理解些 @@ -540,3 +576,4 @@ impl Solution { + diff --git a/problems/0383.赎金信.md b/problems/0383.赎金信.md index e8caa980..eb83d3ec 100644 --- a/problems/0383.赎金信.md +++ b/problems/0383.赎金信.md @@ -176,7 +176,7 @@ class Solution: for x in ransomNote: value = hashmap.get(x) - if not value or not value: + if not value: return False else: hashmap[x] -= 1 diff --git a/problems/0503.下一个更大元素II.md b/problems/0503.下一个更大元素II.md index 62066d85..5751bb91 100644 --- a/problems/0503.下一个更大元素II.md +++ b/problems/0503.下一个更大元素II.md @@ -168,6 +168,7 @@ class Solution { ``` ### Python: +> 版本一： ```python class Solution: @@ -181,6 +182,34 @@ class Solution: stack.append(i%len(nums)) return dp ``` + +> 版本二：针对版本一的优化 + +```python3 +class Solution: + def nextGreaterElements(self, nums: List[int]) -> List[int]: + res = [-1] * len(nums) + stack = [] + #第一次遍历nums + for i, num in enumerate(nums): + while stack and num > nums[stack[-1]]: + res[stack[-1]] = num + stack.pop() + stack.append(i) + #此时stack仍有剩余，有部分数‘无下一个更大元素’待修正 + #第二次遍历nums + for num in nums: + #一旦stack为空，就表明所有数都有下一个更大元素，可以返回结果 + if not stack: + return res + while stack and num > nums[stack[-1]]: + res[stack[-1]] = num + stack.pop() + #不要将已经有下一个更大元素的数加入栈，这样会重复赋值，只需对第一次遍历剩余的数再尝试寻找下一个更大元素即可 + #最后仍有部分最大数无法有下一个更大元素，返回结果 + return res +``` + ### Go: ```go @@ -203,7 +232,6 @@ func nextGreaterElements(nums []int) []int { return result } ``` - ### JavaScript: ```JS diff --git a/problems/0701.二叉搜索树中的插入操作.md b/problems/0701.二叉搜索树中的插入操作.md index 6b9e5834..25d39486 100644 --- a/problems/0701.二叉搜索树中的插入操作.md +++ b/problems/0701.二叉搜索树中的插入操作.md @@ -283,32 +283,10 @@ class Solution: return TreeNode(val) self.traversal(root, val) return root - ``` 递归法（版本二） ```python -class Solution: - def insertIntoBST(self, root, val): - if root is None: - return TreeNode(val) - parent = None - cur = root - while cur: - parent = cur - if val < cur.val: - cur = cur.left - else: - cur = cur.right - if val < parent.val: - parent.left = TreeNode(val) - else: - parent.right = TreeNode(val) - return root -``` - -递归法（版本三） -```python class Solution: def insertIntoBST(self, root: Optional[TreeNode], val: int) -> Optional[TreeNode]: if root is None or root.val == val: @@ -326,7 +304,7 @@ class Solution: return root ``` -递归法（版本四） +递归法（版本三） ```python class Solution: def insertIntoBST(self, root, val): @@ -340,10 +318,9 @@ class Solution: root.right = self.insertIntoBST(root.right, val) return root - ``` -迭代法 +迭代法（版本一） ```python class Solution: def insertIntoBST(self, root, val): @@ -366,10 +343,53 @@ class Solution: else: parent.right = node # 将新节点连接到父节点的右子树 - return root - - + return root ``` + +迭代法（版本二） +```python +class Solution: + def insertIntoBST(self, root, val): + if root is None: + return TreeNode(val) + parent = None + cur = root + while cur: + parent = cur + if val < cur.val: + cur = cur.left + else: + cur = cur.right + if val < parent.val: + parent.left = TreeNode(val) + else: + parent.right = TreeNode(val) + return root +``` + +迭代法（精简） +```python +class Solution: + def insertIntoBST(self, root: Optional[TreeNode], val: int) -> Optional[TreeNode]: + if not root: # 如果根节点为空，创建新节点作为根节点并返回 + return TreeNode(val) + cur = root + while cur: + if val < cur.val: + if not cur.left: # 如果此时父节点的左子树为空 + cur.left = TreeNode(val) # 将新节点连接到父节点的左子树 + return root + else: + cur = cur.left + elif val > cur.val: + if not cur.right: # 如果此时父节点的左子树为空 + cur.right = TreeNode(val) # 将新节点连接到父节点的右子树 + return root + else: + cur = cur.right + +``` + ----- ### Go diff --git a/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md b/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md index 73714147..b0e8b141 100644 --- a/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md +++ b/problems/0714.买卖股票的最佳时机含手续费（动态规划）.md @@ -188,6 +188,20 @@ class Solution: return max(dp[-1][0], dp[-1][1]) ``` +```python +class Solution: + def maxProfit(self, prices: List[int], fee: int) -> int: + # 持有股票手上的最大現金 + hold = -prices[0] - fee + # 不持有股票手上的最大現金 + not_hold = 0 + for price in prices[1:]: + new_hold = max(hold, not_hold - price - fee) + new_not_hold = max(not_hold, hold + price) + hold, not_hold = new_hold, new_not_hold + return not_hold +``` + ### Go： ```go diff --git a/problems/1049.最后一块石头的重量II.md b/problems/1049.最后一块石头的重量II.md index 4f2cc9e3..b40ed114 100644 --- a/problems/1049.最后一块石头的重量II.md +++ b/problems/1049.最后一块石头的重量II.md @@ -313,6 +313,8 @@ class Solution: ``` ### Go： + +一维dp ```go func lastStoneWeightII(stones []int) int { // 15001 = 30 * 1000 /2 +1 @@ -341,6 +343,43 @@ func max(a, b int) int { } ``` +二维dp +```go +func lastStoneWeightII(stones []int) int { + sum := 0 + for _, val := range stones { + sum += val + } + target := sum / 2 + + dp := make([][]int, len(stones)) + for i := range dp { + dp[i] = make([]int, target + 1) + } + for j := stones[0]; j <= target; j++ { + dp[0][j] = stones[0] + } + + for i := 1; i < len(stones); i++ { + for j := 0; j <= target; j++ { + if stones[i] > j { + dp[i][j] = dp[i-1][j] + } else { + dp[i][j] = max(dp[i-1][j], dp[i-1][j-stones[i]] + stones[i]) + } + } + } + return (sum - dp[len(stones)-1][target]) - dp[len(stones)-1][target] +} + +func max(x, y int) int { + if x > y { + return x + } + return y +} +``` + ### JavaScript: ```javascript diff --git a/problems/kamacoder/0044.开发商购买土地.md b/problems/kamacoder/0044.开发商购买土地.md index 37bb98ed..ea2c696e 100644 --- a/problems/kamacoder/0044.开发商购买土地.md +++ b/problems/kamacoder/0044.开发商购买土地.md @@ -388,3 +388,85 @@ if __name__ == "__main__": main() ``` +### C + +前缀和 +```c +#include +#include + +int main() +{ + int n = 0, m = 0, ret_ver = 0, ret_hor = 0; + + // 读取行和列的值 + scanf("%d%d", &n, &m); + // 动态分配数组a(横)和b(纵)的空间 + int *a = (int *)malloc(sizeof(int) * n); + int *b = (int *)malloc(sizeof(int) * m); + + // 初始化数组a和b + for (int i = 0; i < n; i++) + { + a[i] = 0; + } + for (int i = 0; i < m; i++) + { + b[i] = 0; + } + + // 读取区块权值并计算每行和每列的总权值 + for (int i = 0; i < n; i++) + { + for (int j = 0; j < m; j++) + { + int tmp; + scanf("%d", &tmp); + a[i] += tmp; + b[j] += tmp; + } + } + + // 计算每列以及每行的前缀和 + for (int i = 1; i < n; i++) + { + a[i] += a[i - 1]; + } + for (int i = 1; i < m; i++) + { + b[i] += b[i - 1]; + } + + // 初始化ret_ver和ret_hor为最大可能值 + ret_hor = a[n - 1]; + ret_ver = b[m - 1]; + + // 计算按行划分的最小差异 + int ret2 = 0; + while (ret2 < n) + { + ret_hor = (ret_hor > abs(a[n - 1] - 2 * a[ret2])) ? abs(a[n - 1] - 2 * a[ret2]) : ret_hor; + // 原理同列，但更高级 + ret2++; + } + // 计算按列划分的最小差异 + int ret1 = 0; + while (ret1 < m) + { + if (ret_ver > abs(b[m - 1] - 2 * b[ret1])) + { + ret_ver = abs(b[m - 1] - 2 * b[ret1]); + } + ret1++; + } + + // 输出最小差异 + printf("%d\n", (ret_ver <= ret_hor) ? ret_ver : ret_hor); + + // 释放分配的内存 + free(a); + free(b); + return 0; +} + +``` diff --git a/problems/kamacoder/0053.寻宝-Kruskal.md b/problems/kamacoder/0053.寻宝-Kruskal.md index fb816fb1..cb24fd17 100644 --- a/problems/kamacoder/0053.寻宝-Kruskal.md +++ b/problems/kamacoder/0053.寻宝-Kruskal.md @@ -562,4 +562,145 @@ if __name__ == "__main__": ### Dart ### C +并查集方法一 +```c +#include +#include +// 定义边结构体，包含两个顶点vex1和vex2以及它们之间的权重val +struct Edge +{ + int vex1, vex2, val; +}; + +// 冒泡排序函数，用于按边的权重val不减序排序边数组 +void bubblesort(struct Edge *a, int numsize) +{ + for (int i = 0; i < numsize - 1; ++i) + { + + for (int j = 0; j < numsize - i - 1; ++j) + { + if (a[j].val > a[j + 1].val) + { + struct Edge temp = a[j]; + a[j] = a[j + 1]; + a[j + 1] = temp; + } + } + } +} + +int main() +{ + int v, e; + int v1, v2, val; + int ret = 0; + + scanf("%d%d", &v, &e); + struct Edge *edg = (struct Edge *)malloc(sizeof(struct Edge) * e); + int *conne_gra = (int *)malloc(sizeof(int) * (v + 1)); + + // 初始化连通图数组，每个顶点初始时只与自己相连通 + for (int i = 0; i <= v; ++i) + { + conne_gra[i] = i; + } + + // 读取所有边的信息并存储到edg（存储所有边的）数组中 + for (int i = 0; i < e; ++i) + { + scanf("%d%d%d", &v1, &v2, &val); + edg[i].vex1 = v1; + edg[i].vex2 = v2; + edg[i].val = val; + } + bubblesort(edg, e); // 调用冒泡排序函数对边进行排序 + + // 遍历所有边，执行Kruskal算法来找到最小生成树 + for (int i = 0; i < e; ++i) + { + if (conne_gra[edg[i].vex1] != conne_gra[edg[i].vex2]) + { // 如果当前边的两个顶点不在同一个连通分量中 + int tmp1 = conne_gra[edg[i].vex1], tmp2 = conne_gra[edg[i].vex2]; + for (int k = 1; k <= v; ++k) + { // 将所有属于tmp2的顶点合并到tmp1的连通分量中 + if (conne_gra[k] == tmp2) + conne_gra[k] = tmp1; + } + ret += edg[i].val; // 将当前边的权重加到最小生成树的权重中 + } + } + printf("%d", ret); + return 0; +} + +``` +并查集方法二 +```c +#include +#include + +// 定义边结构体，包含两个顶点vex1和vex2以及它们之间的权重val （略，同上） +// 冒泡排序函数，用于按边的权重val不减序排序边数组（略，同上） + +// 并查集的查找操作 +int find(int m, int *father) +{ // 如果当前节点是其自身的父节点，则直接返回该节点 + // 否则递归查找其父节点的根，并将当前节点直接连接到根节点 + return (m == father[m]) ? m : (father[m] = find(father[m], father)); // 路径压缩 +} + +// 并查集的加入集合 +void Union(int m, int n, int *father) +{ + int x = find(m, father); + int y = find(n, father); + if (x == y) + return; // 如果发现根相同，则说明在一个集合，不用两个节点相连直接返回 + father[y] = x; +} + +int main() +{ + int v, e; + int v1, v2, val; + int ret = 0; + + scanf("%d%d", &v, &e); + struct Edge *edg = (struct Edge *)malloc(sizeof(struct Edge) * e); + int *conne_gra = (int *)malloc(sizeof(int) * (v + 1)); + + // 初始化连通图数组，每个顶点初始时只与自己相连通 + for (int i = 0; i <= v; ++i) + { + conne_gra[i] = i; + } + // 读取所有边的信息并存储到edg（存储所有边的）数组中 + for (int i = 0; i < e; ++i) + { + scanf("%d%d%d", &v1, &v2, &val); + edg[i].vex1 = v1; + edg[i].vex2 = v2; + edg[i].val = val; + } + + bubblesort(edg, e); // 调用冒泡排序函数对边进行排序 + + // Kruskal算法的实现，通过边数组构建最小生成树 + int j = 0, count = 0; + while (v > 1) + { + if (find(edg[j].vex1, conne_gra) != find(edg[j].vex2, conne_gra)) + { + ret += edg[j].val; // 将当前边的权重加到最小生成树的权重中 + Union(edg[j].vex1, edg[j].vex2, conne_gra); + v--; + } + j++; + } + printf("%d", ret); + return 0; +} + +``` diff --git a/problems/kamacoder/0058.区间和.md b/problems/kamacoder/0058.区间和.md index f5ce08dc..23e7189a 100644 --- a/problems/kamacoder/0058.区间和.md +++ b/problems/kamacoder/0058.区间和.md @@ -263,3 +263,97 @@ if __name__ == "__main__": main() ``` + + +### JavaScript + +``` JavaScript + +function prefixSum() { + const readline = require('readline'); + + const rl = readline.createInterface({ + input: process.stdin, + output: process.stdout + }); + + let inputLines = []; + rl.on('line', (line) => { + inputLines.push(line.trim()); + }); + + rl.on('close', () => { + // 读取项数 n + const n = parseInt(inputLines[0]); + + // 使用前缀和，复杂度控制在 O(1) + let sum = new Array(n); + sum[0] = parseInt(inputLines[1]); + + // 计算前缀和数组 + for (let i = 1; i < n; i++) { + let value = parseInt(inputLines[i + 1]); + sum[i] = sum[i - 1] + value; + } + + // 处理区间和查询 + for (let i = n + 1; i < inputLines.length; i++) { + let [left, right] = inputLines[i].split(' ').map(Number); + + if (left === 0) { + console.log(sum[right]); + } else { + console.log(sum[right] - sum[left - 1]); + } + } + }); +} + + +``` + + + +### C + +```C +#include +#include + +int main(int argc, char *argv[]) +{ + int num; + // 读取数组长度 + scanf("%d", &num); + + // 使用动态内存分配而不是静态数组，以适应不同的输入大小 + int *a = (int *)malloc((num + 1) * sizeof(int)); + + // 初始化前缀和数组的第一个元素为0 + a[0] = 0; + + // 读取数组元素并计算前缀和 + for (int i = 1; i <= num; i++) + { + int mm; + scanf("%d", &mm); + // 累加前缀和 + a[i] = a[i - 1] + mm; + } + + int m, n; + // 循环读取区间并计算区间和，直到输入结束 + // scanf()返回成功匹配和赋值的个数,到达文件末尾则返回 EOF + while (scanf("%d%d", &m, &n) == 2) + { + // 输出区间和，注意区间是左闭右开，因此a[n+1]是包含n的元素的前缀和 + printf("%d\n", a[n+1] - a[m]); + } + + // 释放之前分配的内存 + free(a); + return 0; +} + +``` + diff --git a/problems/kamacoder/0094.城市间货物运输I-SPFA.md b/problems/kamacoder/0094.城市间货物运输I-SPFA.md index ce383919..b3f42bf8 100644 --- a/problems/kamacoder/0094.城市间货物运输I-SPFA.md +++ b/problems/kamacoder/0094.城市间货物运输I-SPFA.md @@ -425,7 +425,39 @@ public class Main { ``` ### Python +```Python +import collections +def main(): + n, m = map(int, input().strip().split()) + edges = [[] for _ in range(n + 1)] + for _ in range(m): + src, dest, weight = map(int, input().strip().split()) + edges[src].append([dest, weight]) + + minDist = [float("inf")] * (n + 1) + minDist[1] = 0 + que = collections.deque([1]) + visited = [False] * (n + 1) + visited[1] = True + + while que: + cur = que.popleft() + visited[cur] = False + for dest, weight in edges[cur]: + if minDist[cur] != float("inf") and minDist[cur] + weight < minDist[dest]: + minDist[dest] = minDist[cur] + weight + if visited[dest] == False: + que.append(dest) + visited[dest] = True + + if minDist[-1] == float("inf"): + return "unconnected" + return minDist[-1] + +if __name__ == "__main__": + print(main()) +``` ### Go ### Rust diff --git a/problems/kamacoder/0094.城市间货物运输I.md b/problems/kamacoder/0094.城市间货物运输I.md index 45ca1313..3737fe01 100644 --- a/problems/kamacoder/0094.城市间货物运输I.md +++ b/problems/kamacoder/0094.城市间货物运输I.md @@ -451,6 +451,33 @@ public class Main { ``` ### Python +```Python +def main(): + n, m = map(int, input().strip().split()) + edges = [] + for _ in range(m): + src, dest, weight = map(int, input().strip().split()) + edges.append([src, dest, weight]) + + minDist = [float("inf")] * (n + 1) + minDist[1] = 0 # 起点处距离为0 + + for i in range(1, n): + updated = False + for src, dest, weight in edges: + if minDist[src] != float("inf") and minDist[src] + weight < minDist[dest]: + minDist[dest] = minDist[src] + weight + updated = True + if not updated: # 若边不再更新，即停止回圈 + break + + if minDist[-1] == float("inf"): # 返还终点权重 + return "unconnected" + return minDist[-1] + +if __name__ == "__main__": + print(main()) +``` ### Go diff --git a/problems/kamacoder/0099.岛屿的数量广搜.md b/problems/kamacoder/0099.岛屿的数量广搜.md index 9fca9a04..30475753 100644 --- a/problems/kamacoder/0099.岛屿的数量广搜.md +++ b/problems/kamacoder/0099.岛屿的数量广搜.md @@ -191,10 +191,57 @@ int main() { ### Java ```java +import java.util.*; +public class Main { + public static int[][] dir = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};//下右上左逆时针遍历 + public static void bfs(int[][] grid, boolean[][] visited, int x, int y) { + Queue queue = new LinkedList();//定义坐标队列，没有现成的pair类，在下面自定义了 + queue.add(new pair(x, y)); + visited[x][y] = true;//遇到入队直接标记为优先， + // 否则出队时才标记的话会导致重复访问，比如下方节点会在右下顺序的时候被第二次访问入队 + while (!queue.isEmpty()) { + int curX = queue.peek().first; + int curY = queue.poll().second;//当前横纵坐标 + for (int i = 0; i < 4; i++) { + //顺时针遍历新节点next，下面记录坐标 + int nextX = curX + dir[i][0]; + int nextY = curY + dir[i][1]; + if (nextX < 0 || nextX >= grid.length || nextY < 0 || nextY >= grid[0].length) { + continue; + }//去除越界部分 + if (!visited[nextX][nextY] && grid[nextX][nextY] == 1) { + queue.add(new pair(nextX, nextY)); + visited[nextX][nextY] = true;//逻辑同上 + } + } + } + } - + public static void main(String[] args) { + Scanner sc = new Scanner(System.in); + int m = sc.nextInt(); + int n = sc.nextInt(); + int[][] grid = new int[m][n]; + boolean[][] visited = new boolean[m][n]; + int ans = 0; + for (int i = 0; i < m; i++) { + for (int j = 0; j < n; j++) { + grid[i][j] = sc.nextInt(); + } + } + for (int i = 0; i < m; i++) { + for (int j = 0; j < n; j++) { + if (!visited[i][j] && grid[i][j] == 1) { + ans++; + bfs(grid, visited, i, j); + } + } + } + System.out.println(ans); + } +} ``` diff --git a/problems/kamacoder/0099.岛屿的数量深搜.md b/problems/kamacoder/0099.岛屿的数量深搜.md index b257ca9a..6ac7ba3b 100644 --- a/problems/kamacoder/0099.岛屿的数量深搜.md +++ b/problems/kamacoder/0099.岛屿的数量深搜.md @@ -182,7 +182,52 @@ int main() { ## 其他语言版本 ### Java +```java +import java.util.Scanner; +public class Main { + public static int[][] dir ={{0,1},{1,0},{-1,0},{0,-1}}; + public static void dfs(boolean[][] visited,int x,int y ,int [][]grid) + { + for (int i = 0; i < 4; i++) { + int nextX=x+dir[i][0]; + int nextY=y+dir[i][1]; + if(nextY<0||nextX<0||nextX>= grid.length||nextY>=grid[0].length) + continue; + if(!visited[nextX][nextY]&&grid[nextX][nextY]==1) + { + visited[nextX][nextY]=true; + dfs(visited,nextX,nextY,grid); + } + } + } + public static void main(String[] args) { + Scanner sc = new Scanner(System.in); + int m= sc.nextInt(); + int n = sc.nextInt(); + int[][] grid = new int[m][n]; + for (int i = 0; i < m; i++) { + for (int j = 0; j < n; j++) { + grid[i][j]=sc.nextInt(); + } + } + boolean[][]visited =new boolean[m][n]; + int ans = 0; + for (int i = 0; i < m; i++) { + for (int j = 0; j < n; j++) { + if(!visited[i][j]&&grid[i][j]==1) + { + ans++; + visited[i][j]=true; + dfs(visited,i,j,grid); + } + } + } + System.out.println(ans); + } +} + +``` ### Python 版本一 diff --git a/problems/kamacoder/0105.有向图的完全可达性.md b/problems/kamacoder/0105.有向图的完全可达性.md index cd880a83..838b0212 100644 --- a/problems/kamacoder/0105.有向图的完全可达性.md +++ b/problems/kamacoder/0105.有向图的完全可达性.md @@ -289,6 +289,69 @@ int main() { ### Java +```java + +import java.util.*; + +public class Main { + public static List> adjList = new ArrayList<>(); + + public static void dfs(boolean[] visited, int key) { + if (visited[key]) { + return; + } + visited[key] = true; + List nextKeys = adjList.get(key); + for (int nextKey : nextKeys) { + dfs(visited, nextKey); + } + } + + public static void bfs(boolean[] visited, int key) { + Queue queue = new LinkedList(); + queue.add(key); + visited[key] = true; + while (!queue.isEmpty()) { + int curKey = queue.poll(); + List list = adjList.get(curKey); + for (int nextKey : list) { + if (!visited[nextKey]) { + queue.add(nextKey); + visited[nextKey] = true; + } + } + } + } + + public static void main(String[] args) { + Scanner sc = new Scanner(System.in); + int vertices_num = sc.nextInt(); + int line_num = sc.nextInt(); + for (int i = 0; i < vertices_num; i++) { + adjList.add(new LinkedList<>()); + }//Initialization + for (int i = 0; i < line_num; i++) { + int s = sc.nextInt(); + int t = sc.nextInt(); + adjList.get(s - 1).add(t - 1); + }//构造邻接表 + boolean[] visited = new boolean[vertices_num]; + dfs(visited, 0); +// bfs(visited, 0); + + for (int i = 0; i < vertices_num; i++) { + if (!visited[i]) { + System.out.println(-1); + return; + } + } + System.out.println(1); + } +} + +``` + + ### Python BFS算法 ```Python @@ -327,8 +390,103 @@ if __name__ == "__main__": ``` +``` python + +def dfs(graph, key, visited): + for neighbor in graph[key]: + if not visited[neighbor]: # Check if the next node is not visited + visited[neighbor] = True + dfs(graph, neighbor, visited) + +def main(): + import sys + input = sys.stdin.read + data = input().split() + + n = int(data[0]) + m = int(data[1]) + + graph = [[] for _ in range(n + 1)] + index = 2 + for _ in range(m): + s = int(data[index]) + t = int(data[index + 1]) + graph[s].append(t) + index += 2 + + visited = [False] * (n + 1) + visited[1] = True # Process node 1 beforehand + dfs(graph, 1, visited) + + for i in range(1, n + 1): + if not visited[i]: + print(-1) + return + + print(1) + +if __name__ == "__main__": + main() + + +``` + ### Go +```go + +package main + +import ( + "bufio" + "fmt" + "os" +) + +func dfs(graph [][]int, key int, visited []bool) { + visited[key] = true + for _, neighbor := range graph[key] { + if !visited[neighbor] { + dfs(graph, neighbor, visited) + } + } +} + +func main() { + scanner := bufio.NewScanner(os.Stdin) + scanner.Scan() + var n, m int + fmt.Sscanf(scanner.Text(), "%d %d", &n, &m) + + graph := make([][]int, n+1) + for i := 0; i <= n; i++ { + graph[i] = make([]int, 0) + } + + for i := 0; i < m; i++ { + scanner.Scan() + var s, t int + fmt.Sscanf(scanner.Text(), "%d %d", &s, &t) + graph[s] = append(graph[s], t) + } + + visited := make([]bool, n+1) + + dfs(graph, 1, visited) + + for i := 1; i <= n; i++ { + if !visited[i] { + fmt.Println(-1) + return + } + } + fmt.Println(1) +} + + +``` + + ### Rust ### Javascript diff --git a/problems/kamacoder/0106.岛屿的周长.md b/problems/kamacoder/0106.岛屿的周长.md index 6f3462c5..235d9445 100644 --- a/problems/kamacoder/0106.岛屿的周长.md +++ b/problems/kamacoder/0106.岛屿的周长.md @@ -216,8 +216,131 @@ public class Main { ### Python +```python + +def main(): + import sys + input = sys.stdin.read + data = input().split() + + # 读取 n 和 m + n = int(data[0]) + m = int(data[1]) + + # 初始化 grid + grid = [] + index = 2 + for i in range(n): + grid.append([int(data[index + j]) for j in range(m)]) + index += m + + sum_land = 0 # 陆地数量 + cover = 0 # 相邻数量 + + for i in range(n): + for j in range(m): + if grid[i][j] == 1: + sum_land += 1 + # 统计上边相邻陆地 + if i - 1 >= 0 and grid[i - 1][j] == 1: + cover += 1 + # 统计左边相邻陆地 + if j - 1 >= 0 and grid[i][j - 1] == 1: + cover += 1 + # 不统计下边和右边，避免重复计算 + + result = sum_land * 4 - cover * 2 + print(result) + +if __name__ == "__main__": + main() + + +``` + ### Go +```go + +package main + +import ( + "bufio" + "fmt" + "os" + "strconv" + "strings" +) + +func main() { + scanner := bufio.NewScanner(os.Stdin) + scanner.Scan() + line := scanner.Text() + + n, m := parseInput(line) + + // 初始化 grid + grid := make([][]int, n) + for i := range grid { + grid[i] = make([]int, m) + } + + // 读入 grid 数据 + for i := 0; i < n; i++ { + scanner.Scan() + line := scanner.Text() + values := parseLine(line, m) + for j := 0; j < m; j++ { + grid[i][j] = values[j] + } + } + + sum := 0 // 陆地数量 + cover := 0 // 相邻数量 + + for i := 0; i < n; i++ { + for j := 0; j < m; j++ { + if grid[i][j] == 1 { + sum++ // 统计总的陆地数量 + + // 统计上边相邻陆地 + if i-1 >= 0 && grid[i-1][j] == 1 { + cover++ + } + // 统计左边相邻陆地 + if j-1 >= 0 && grid[i][j-1] == 1 { + cover++ + } + // 为什么没统计下边和右边？ 因为避免重复计算 + } + } + } + + fmt.Println(sum*4 - cover*2) +} + +// parseInput 解析 n 和 m +func parseInput(line string) (int, int) { + parts := strings.Split(line, " ") + n, _ := strconv.Atoi(parts[0]) + m, _ := strconv.Atoi(parts[1]) + return n, m +} + +// parseLine 解析一行中的多个值 +func parseLine(line string, count int) []int { + parts := strings.Split(line, " ") + values := make([]int, count) + for i := 0; i < count; i++ { + values[i], _ = strconv.Atoi(parts[i]) + } + return values +} + + +``` + + ### Rust ### Javascript diff --git a/problems/背包理论基础01背包-2.md b/problems/背包理论基础01背包-2.md index b665070c..b5862bb5 100644 --- a/problems/背包理论基础01背包-2.md +++ b/problems/背包理论基础01背包-2.md @@ -298,23 +298,18 @@ public class Main { ```python n, bagweight = map(int, input().split()) - weight = list(map(int, input().split())) value = list(map(int, input().split())) -dp = [[0] * (bagweight + 1) for _ in range(n)] +dp = [0] * (bagweight + 1) # 创建一个动态规划数组dp，初始值为0 -for j in range(weight[0], bagweight + 1): - dp[0][j] = value[0] +dp[0] = 0 # 初始化dp[0] = 0,背包容量为0，价值最大为0 -for i in range(1, n): - for j in range(bagweight + 1): - if j < weight[i]: - dp[i][j] = dp[i - 1][j] - else: - dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - weight[i]] + value[i]) +for i in range(n): # 应该先遍历物品，如果遍历背包容量放在上一层，那么每个dp[j]就只会放入一个物品 + for j in range(bagweight, weight[i]-1, -1): # 倒序遍历背包容量是为了保证物品i只被放入一次 + dp[j] = max(dp[j], dp[j - weight[i]] + value[i]) -print(dp[n - 1][bagweight]) +print(dp[bagweight]) ``` ### Go