From d92aa2c52f0589cca9dbf1a7624f9312395b63fe Mon Sep 17 00:00:00 2001 From: unknown Date: Wed, 11 May 2022 00:39:59 +0100 Subject: [PATCH 1/5] =?UTF-8?q?Add=200112.=E8=B7=AF=E5=BE=84=E6=80=BB?= =?UTF-8?q?=E5=92=8C.md=20C=E8=AF=AD=E8=A8=80=E8=A7=A3=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0112.路径总和.md | 57 +++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/problems/0112.路径总和.md b/problems/0112.路径总和.md index 41463ec1..6433996c 100644 --- a/problems/0112.路径总和.md +++ b/problems/0112.路径总和.md @@ -1006,6 +1006,63 @@ func traversal(_ cur: TreeNode?, count: Int) { } ``` +## C +0112.路径总和 +递归法： +```c +bool hasPathSum(struct TreeNode* root, int targetSum){ + // 递归结束条件：若当前节点不存在，返回false + if(!root) + return false; + // 若当前节点为叶子节点，且targetSum-root的值为0。（当前路径上的节点值的和满足条件）返回true + if(!root->right && !root->left && targetSum == root->val) + return true; + + // 查看左子树和右子树的所有节点是否满足条件 + return hasPathSum(root->right, targetSum - root->val) || hasPathSum(root->left, targetSum - root->val); +} +``` + +迭代法: +```c +// 存储一个节点以及当前的和 +struct Pair { + struct TreeNode* node; + int sum; +}; + +bool hasPathSum(struct TreeNode* root, int targetSum){ + struct Pair stack[1000]; + int stackTop = 0; + + // 若root存在，则将节点和值封装成一个pair入栈 + if(root) { + struct Pair newPair = {root, root->val}; + stack[stackTop++] = newPair; + } + + // 当栈不为空时 + while(stackTop) { + // 出栈栈顶元素 + struct Pair topPair = stack[--stackTop]; + // 若栈顶元素为叶子节点，且和为targetSum时，返回true + if(!topPair.node->left && !topPair.node->right && topPair.sum == targetSum) + return true; + + // 若当前栈顶节点有左右孩子，计算和并入栈 + if(topPair.node->left) { + struct Pair newPair = {topPair.node->left, topPair.sum + topPair.node->left->val}; + stack[stackTop++] = newPair; + } + if(topPair.node->right) { + struct Pair newPair = {topPair.node->right, topPair.sum + topPair.node->right->val}; + stack[stackTop++] = newPair; + } + } + return false; +} +``` + ----------------------- From cb2fea63e7f5e616f697a715b9d523b6ba877308 Mon Sep 17 00:00:00 2001 From: unknown Date: Wed, 11 May 2022 09:50:47 +0100 Subject: [PATCH 2/5] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200113.=E8=B7=AF?= =?UTF-8?q?=E5=BE=84=E6=80=BB=E5=92=8CII=20C=E8=AF=AD=E8=A8=80=E8=A7=A3?= =?UTF-8?q?=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0112.路径总和.md | 65 ++++++++++++++++++++++++++++++++++- 1 file changed, 64 insertions(+), 1 deletion(-) diff --git a/problems/0112.路径总和.md b/problems/0112.路径总和.md index 6433996c..de155b45 100644 --- a/problems/0112.路径总和.md +++ b/problems/0112.路径总和.md @@ -1007,7 +1007,7 @@ func traversal(_ cur: TreeNode?, count: Int) { ``` ## C -0112.路径总和 +> 0112.路径总和 递归法： ```c bool hasPathSum(struct TreeNode* root, int targetSum){ @@ -1062,6 +1062,69 @@ bool hasPathSum(struct TreeNode* root, int targetSum){ return false; } ``` +> 0113.路径总和 II +```c +int** ret; +int* path; +int* colSize; +int retTop; +int pathTop; + +void traversal(const struct TreeNode* const node, int count) { + // 若当前节点为叶子节点 + if(!node->right && !node->left) { + // 若当前path上的节点值总和等于targetSum。 + if(count == 0) { + // 复制当前path + int *curPath = (int*)malloc(sizeof(int) * pathTop); + memcpy(curPath, path, sizeof(int) * pathTop); + // 记录当前path的长度为pathTop + colSize[retTop] = pathTop; + // 将当前path加入到ret数组中 + ret[retTop++] = curPath; + } + return; + } + + // 若节点有左/右孩子 + if(node->left) { + // 将左孩子的值加入path中 + path[pathTop++] = node->left->val; + traversal(node->left, count - node->left->val); + // 回溯 + pathTop--; + } + if(node->right) { + // 将右孩子的值加入path中 + path[pathTop++] = node->right->val; + traversal(node->right, count - node->right->val); + // 回溯 + --pathTop; + } +} + +int** pathSum(struct TreeNode* root, int targetSum, int* returnSize, int** returnColumnSizes){ + // 初始化数组 + ret = (int**)malloc(sizeof(int*) * 1000); + path = (int*)malloc(sizeof(int*) * 1000); + colSize = (int*)malloc(sizeof(int) * 1000); + retTop = pathTop = 0; + *returnSize = 0; + + // 若根节点不存在，返回空的ret + if(!root) + return ret; + // 将根节点加入到path中 + path[pathTop++] = root->val; + traversal(root, targetSum - root->val); + + // 设置返回ret数组大小，以及其中每个一维数组元素的长度 + *returnSize = retTop; + *returnColumnSizes = colSize; + + return ret; +} +``` From 5da6c06ef9fd308e9ab77b8393e81377eec75821 Mon Sep 17 00:00:00 2001 From: unknown Date: Sat, 14 May 2022 16:27:47 +0100 Subject: [PATCH 3/5] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20=E8=83=8C=E5=8C=85?= =?UTF-8?q?=E7=90=86=E8=AE=BA=E8=82=8C=E9=86=8701=E8=83=8C=E5=8C=85=20C?= =?UTF-8?q?=E8=AF=AD=E8=A8=80=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/背包理论基础01背包-1.md | 46 ++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/problems/背包理论基础01背包-1.md b/problems/背包理论基础01背包-1.md index fe940b4c..43ad26be 100644 --- a/problems/背包理论基础01背包-1.md +++ b/problems/背包理论基础01背包-1.md @@ -423,5 +423,51 @@ function test () { test(); ``` +### C +```c +#include +#include +#include + +#define MAX(a, b) (((a) > (b)) ? (a) : (b)) +#define ARR_SIZE(a) (sizeof((a)) / sizeof((a)[0])) +#define BAG_WEIGHT 4 + +void backPack(int* weights, int weightSize, int* costs, int costSize, int bagWeight) { + // 开辟dp数组 + int dp[weightSize][bagWeight + 1]; + memset(dp, 0, sizeof(int) * weightSize * (bagWeight + 1)); + + int i, j; + // 当背包容量大于物品0的重量时，将物品0放入到背包中 + for(j = weights[0]; j <= bagWeight; ++j) { + dp[0][j] = costs[0]; + } + + // 先遍历物品，再遍历重量 + for(j = 1; j <= bagWeight; ++j) { + for(i = 1; i < weightSize; ++i) { + // 如果当前背包容量小于物品重量 + if(j < weights[i]) + // 背包物品的价值等于背包不放置当前物品时的价值 + dp[i][j] = dp[i-1][j]; + // 若背包当前重量可以放置物品 + else + // 背包的价值等于放置该物品或不放置该物品的最大值 + dp[i][j] = MAX(dp[i - 1][j], dp[i - 1][j - weights[i]] + costs[i]); + } + } + + printf("%d\n", dp[weightSize - 1][bagWeight]); +} + +int main(int argc, char* argv[]) { + int weights[] = {1, 3, 4}; + int costs[] = {15, 20, 30}; + backPack(weights, ARR_SIZE(weights), costs, ARR_SIZE(costs), BAG_WEIGHT); + return 0; +} +``` + -----------------------
From aa22b802a5986f06a123c59f395bf49aba779d1a Mon Sep 17 00:00:00 2001 From: unknown Date: Sun, 15 May 2022 14:39:41 +0100 Subject: [PATCH 4/5] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20=E8=83=8C=E5=8C=85?= =?UTF-8?q?=E7=90=86=E8=AE=BA=E5=9F=BA=E7=A1=8001-2.mc=20C=E8=AF=AD?= =?UTF-8?q?=E8=A8=80=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/背包理论基础01背包-2.md | 33 ++++++++++++++++++++++++ 1 file changed, 33 insertions(+) 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 dabdfb2d..a99a872b 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 @@ -315,6 +315,39 @@ function test () { test(); ``` +### C +```c +#include +#include + +#define MAX(a, b) (((a) > (b)) ? (a) : (b)) +#define ARR_SIZE(arr) ((sizeof((arr))) / sizeof((arr)[0])) +#define BAG_WEIGHT 4 + +void test_back_pack(int* weights, int weightSize, int* values, int valueSize, int bagWeight) { + int dp[bagWeight + 1]; + memset(dp, 0, sizeof(int) * (bagWeight + 1)); + + int i, j; + // 先遍历物品 + for(i = 0; i < weightSize; ++i) { + // 后遍历重量。从后向前遍历 + for(j = bagWeight; j >= weights[i]; --j) { + dp[j] = MAX(dp[j], dp[j - weights[i]] + values[i]); + } + } + + // 打印最优结果 + printf("%d\n", dp[bagWeight]); +} + +int main(int argc, char** argv) { + int weights[] = {1, 3, 4}; + int values[] = {15, 20, 30}; + test_back_pack(weights, ARR_SIZE(weights), values, ARR_SIZE(values), BAG_WEIGHT); + return 0; +} +``` ----------------------- From 19abe18019814af74ee51ba56e4e8ee6106b1253 Mon Sep 17 00:00:00 2001 From: unknown Date: Sun, 15 May 2022 15:26:23 +0100 Subject: [PATCH 5/5] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200416.=E5=88=86?= =?UTF-8?q?=E5=89=B2=E7=AD=89=E5=92=8C=E5=AD=90=E9=9B=86.md=20C=E8=AF=AD?= =?UTF-8?q?=E8=A8=80=E7=89=88=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0416.分割等和子集.md | 100 ++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) diff --git a/problems/0416.分割等和子集.md b/problems/0416.分割等和子集.md index 6e93ae8e..76cfd87f 100644 --- a/problems/0416.分割等和子集.md +++ b/problems/0416.分割等和子集.md @@ -416,6 +416,106 @@ var canPartition = function(nums) { }; ``` +C: +二维dp： +```c +/** +1. dp数组含义：dp[i][j]为背包重量为j时，从[0-i]元素和最大值 +2. 递推公式：dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - nums[i]] + nums[i]) +3. 初始化：dp[i][0]初始化为0。因为背包重量为0时，不可能放入元素。dp[0][j] = nums[0]，当j >= nums[0] && j < target时 +4. 遍历顺序：先遍历物品，再遍历背包 +*/ +#define MAX(a, b) (((a) > (b)) ? (a) : (b)) + +int getSum(int* nums, int numsSize) { + int sum = 0; + + int i; + for(i = 0; i < numsSize; ++i) { + sum += nums[i]; + } + return sum; +} + +bool canPartition(int* nums, int numsSize){ + // 求出元素总和 + int sum = getSum(nums, numsSize); + // 若元素总和为奇数，则不可能得到两个和相等的子数组 + if(sum % 2) + return false; + + // 若子数组的和等于target，则nums可以被分割 + int target = sum / 2; + // 初始化dp数组 + int dp[numsSize][target + 1]; + // dp[j][0]都应被设置为0。因为当背包重量为0时，不可放入元素 + memset(dp, 0, sizeof(int) * numsSize * (target + 1)); + + int i, j; + // 当背包重量j大于nums[0]时，可以在dp[0][j]中放入元素nums[0] + for(j = nums[0]; j <= target; ++j) { + dp[0][j] = nums[0]; + } + + for(i = 1; i < numsSize; ++i) { + for(j = 1; j <= target; ++j) { + // 若当前背包重量j小于nums[i]，则其值等于只考虑0到i-1物品时的值 + if(j < nums[i]) + dp[i][j] = dp[i - 1][j]; + // 否则，背包重量等于在背包中放入num[i]/不放入nums[i]的较大值 + else + dp[i][j] = MAX(dp[i - 1][j], dp[i - 1][j - nums[i]] + nums[i]); + } + } + // 判断背包重量为target，且考虑到所有物品时，放入的元素和是否等于target + return dp[numsSize - 1][target] == target; +} +``` +滚动数组： +```c +/** +1. dp数组含义：dp[j]为背包重量为j时，其中可放入元素的最大值 +2. 递推公式：dp[j] = max(dp[j], dp[j - nums[i]] + nums[i]) +3. 初始化：均初始化为0即可 +4. 遍历顺序：先遍历物品，再后序遍历背包 +*/ +#define MAX(a, b) (((a) > (b)) ? (a) : (b)) + +int getSum(int* nums, int numsSize) { + int sum = 0; + + int i; + for(i = 0; i < numsSize; ++i) { + sum += nums[i]; + } + return sum; +} + +bool canPartition(int* nums, int numsSize){ + // 求出元素总和 + int sum = getSum(nums, numsSize); + // 若元素总和为奇数，则不可能得到两个和相等的子数组 + if(sum % 2) + return false; + // 背包容量 + int target = sum / 2; + + // 初始化dp数组，元素均为0 + int dp[target + 1]; + memset(dp, 0, sizeof(int) * (target + 1)); + + int i, j; + // 先遍历物品，后遍历背包 + for(i = 0; i < numsSize; ++i) { + for(j = target; j >= nums[i]; --j) { + dp[j] = MAX(dp[j], dp[j - nums[i]] + nums[i]); + } + } + + // 查看背包容量为target时，元素总和是否等于target + return dp[target] == target; +} +```