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Merge branch 'master' of github.com:youngyangyang04/leetcode-master
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@ -191,33 +191,48 @@ class Solution {
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python:
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```python
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```python3
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class Solution:
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def generateMatrix(self, n: int) -> List[List[int]]:
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left, right, up, down = 0, n-1, 0, n-1
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matrix = [ [0]*n for _ in range(n)]
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num = 1
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while left<=right and up<=down:
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# 填充左到右
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for i in range(left, right+1):
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matrix[up][i] = num
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num += 1
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up += 1
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# 填充上到下
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for i in range(up, down+1):
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matrix[i][right] = num
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num += 1
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right -= 1
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# 填充右到左
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for i in range(right, left-1, -1):
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matrix[down][i] = num
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num += 1
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down -= 1
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# 填充下到上
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for i in range(down, up-1, -1):
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matrix[i][left] = num
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num += 1
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# 初始化要填充的正方形
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matrix = [[0] * n for _ in range(n)]
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left, right, up, down = 0, n - 1, 0, n - 1
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number = 1 # 要填充的数字
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while left < right and up < down:
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# 从左到右填充上边
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for x in range(left, right):
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matrix[up][x] = number
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number += 1
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# 从上到下填充右边
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for y in range(up, down):
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matrix[y][right] = number
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number += 1
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# 从右到左填充下边
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for x in range(right, left, -1):
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matrix[down][x] = number
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number += 1
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# 从下到上填充左边
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for y in range(down, up, -1):
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matrix[y][left] = number
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number += 1
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# 缩小要填充的范围
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left += 1
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right -= 1
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up += 1
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down -= 1
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# 如果阶数为奇数,额外填充一次中心
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if n % 2:
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matrix[n // 2][n // 2] = number
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return matrix
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```
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@ -29,7 +29,7 @@
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与198.打家劫舍,213.打家劫舍II一样,关键是要讨论当前节点抢还是不抢。
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如果抢了当前节点,两个孩子就不是动,如果没抢当前节点,就可以考虑抢左右孩子(**注意这里说的是“考虑”**)
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如果抢了当前节点,两个孩子就不能动,如果没抢当前节点,就可以考虑抢左右孩子(**注意这里说的是“考虑”**)
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### 暴力递归
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@ -91,7 +91,7 @@ public:
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### 动态规划
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在上面两种方法,其实对一个节点 投与不投得到的最大金钱都没有做记录,而是需要实时计算。
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在上面两种方法,其实对一个节点 偷与不偷得到的最大金钱都没有做记录,而是需要实时计算。
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而动态规划其实就是使用状态转移容器来记录状态的变化,这里可以使用一个长度为2的数组,记录当前节点偷与不偷所得到的的最大金钱。
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@ -121,7 +121,7 @@ vector<int> robTree(TreeNode* cur) {
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2. 确定终止条件
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在遍历的过程中,如果遇到空间点的话,很明显,无论偷还是不偷都是0,所以就返回
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在遍历的过程中,如果遇到空节点的话,很明显,无论偷还是不偷都是0,所以就返回
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```
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if (cur == NULL) return vector<int>{0, 0};
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```
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@ -9,6 +9,10 @@
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# 673.最长递增子序列的个数
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[力扣题目链接](https://leetcode-cn.com/problems/number-of-longest-increasing-subsequence/)
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给定一个未排序的整数数组,找到最长递增子序列的个数。
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示例 1:
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@ -224,16 +228,110 @@ public:
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## Java
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```java
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class Solution {
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public int findNumberOfLIS(int[] nums) {
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if (nums.length <= 1) return nums.length;
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int[] dp = new int[nums.length];
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for(int i = 0; i < dp.length; i++) dp[i] = 1;
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int[] count = new int[nums.length];
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for(int i = 0; i < count.length; i++) count[i] = 1;
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int maxCount = 0;
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for (int i = 1; i < nums.length; i++) {
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for (int j = 0; j < i; j++) {
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if (nums[i] > nums[j]) {
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if (dp[j] + 1 > dp[i]) {
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dp[i] = dp[j] + 1;
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count[i] = count[j];
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} else if (dp[j] + 1 == dp[i]) {
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count[i] += count[j];
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}
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}
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if (dp[i] > maxCount) maxCount = dp[i];
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}
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}
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int result = 0;
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for (int i = 0; i < nums.length; i++) {
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if (maxCount == dp[i]) result += count[i];
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}
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return result;
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}
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}
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```
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## Python
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```python
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class Solution:
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def findNumberOfLIS(self, nums: List[int]) -> int:
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size = len(nums)
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if size<= 1: return size
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dp = [1 for i in range(size)]
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count = [1 for i in range(size)]
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maxCount = 0
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for i in range(1, size):
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for j in range(i):
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if nums[i] > nums[j]:
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if dp[j] + 1 > dp[i] :
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dp[i] = dp[j] + 1
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count[i] = count[j]
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elif dp[j] + 1 == dp[i] :
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count[i] += count[j]
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if dp[i] > maxCount:
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maxCount = dp[i];
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result = 0
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for i in range(size):
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if maxCount == dp[i]:
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result += count[i]
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return result;
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```
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## Go
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```go
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func findNumberOfLIS(nums []int) int {
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size := len(nums)
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if size <= 1 {
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return size
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}
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dp := make([]int, size);
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for i, _ := range dp {
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dp[i] = 1
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}
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count := make([]int, size);
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for i, _ := range count {
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count[i] = 1
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}
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maxCount := 0
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for i := 1; i < size; i++ {
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for j := 0; j < i; j++ {
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if nums[i] > nums[j] {
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if dp[j] + 1 > dp[i] {
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dp[i] = dp[j] + 1
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count[i] = count[j]
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} else if dp[j] + 1 == dp[i] {
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count[i] += count[j]
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}
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}
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if dp[i] > maxCount {
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maxCount = dp[i]
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}
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}
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}
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result := 0
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for i := 0; i < size; i++ {
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if maxCount == dp[i] {
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result += count[i]
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}
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}
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return result
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}
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```
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## JavaScript
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@ -117,11 +117,8 @@ class Solution {
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}
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// 如果K还大于0,那么反复转变数值最小的元素,将K用完
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if (k % 2 == 1) nums[len - 1] = -nums[len - 1];
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int result = 0;
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for (int a : nums) {
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result += a;
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}
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return result;
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return Arrays.stream(nums).sum();
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}
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}
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```
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@ -80,7 +80,7 @@ dp状态图如下:
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* [动态规划:关于01背包问题,你该了解这些!](https://programmercarl.com/背包理论基础01背包-1.html)
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* [动态规划:关于01背包问题,你该了解这些!(滚动数组)](https://programmercarl.com/背包理论基础01背包-2.html)
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就知道了,01背包中二维dp数组的两个for遍历的先后循序是可以颠倒了,一位dp数组的两个for循环先后循序一定是先遍历物品,再遍历背包容量。
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就知道了,01背包中二维dp数组的两个for遍历的先后循序是可以颠倒了,一维dp数组的两个for循环先后循序一定是先遍历物品,再遍历背包容量。
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**在完全背包中,对于一维dp数组来说,其实两个for循环嵌套顺序同样无所谓!**
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Reference in New Issue
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