diff --git "a/problems/0019.345円210円240円351円231円244円351円223円276円350円241円250円347円232円204円345円200円222円346円225円260円347円254円254円N344円270円252円350円212円202円347円202円271円.md" "b/problems/0019.345円210円240円351円231円244円351円223円276円350円241円250円347円232円204円345円200円222円346円225円260円347円254円254円N344円270円252円350円212円202円347円202円271円.md" index 813e9b02fa..b3030a81d1 100644 --- "a/problems/0019.345円210円240円351円231円244円351円223円276円350円241円250円347円232円204円345円200円222円346円225円260円347円254円254円N344円270円252円350円212円202円347円202円271円.md" +++ "b/problems/0019.345円210円240円351円231円244円351円223円276円350円241円250円347円232円204円345円200円222円346円225円260円347円254円254円N344円270円252円350円212円202円347円202円271円.md" @@ -39,7 +39,7 @@ 分为如下几步: -* 首先这里我推荐大家使用虚拟头结点,这样方面处理删除实际头结点的逻辑,如果虚拟头结点不清楚,可以看这篇: [链表:听说用虚拟头节点会方便很多?](https://programmercarl.com/0203.移除链表元素.html) +* 首先这里我推荐大家使用虚拟头结点,这样方便处理删除实际头结点的逻辑,如果虚拟头结点不清楚,可以看这篇: [链表:听说用虚拟头节点会方便很多?](https://programmercarl.com/0203.移除链表元素.html) * 定义fast指针和slow指针,初始值为虚拟头结点,如图: diff --git "a/problems/0027.347円247円273円351円231円244円345円205円203円347円264円240円.md" "b/problems/0027.347円247円273円351円231円244円345円205円203円347円264円240円.md" index 590cf0b924..3a93ac8820 100644 --- "a/problems/0027.347円247円273円351円231円244円345円205円203円347円264円240円.md" +++ "b/problems/0027.347円247円273円351円231円244円345円205円203円347円264円240円.md" @@ -81,7 +81,7 @@ public: **双指针法(快慢指针法)在数组和链表的操作中是非常常见的,很多考察数组、链表、字符串等操作的面试题,都使用双指针法。** -后序都会一一介绍到,本题代码如下: +后续都会一一介绍到,本题代码如下: ```CPP // 时间复杂度:O(n) diff --git "a/problems/0112.350円267円257円345円276円204円346円200円273円345円222円214円.md" "b/problems/0112.350円267円257円345円276円204円346円200円273円345円222円214円.md" index 2fdd77417e..d3eec16b9e 100644 --- "a/problems/0112.350円267円257円345円276円204円346円200円273円345円222円214円.md" +++ "b/problems/0112.350円267円257円345円276円204円346円200円273円345円222円214円.md" @@ -1006,6 +1006,126 @@ 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; +} +``` +> 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; +} +``` + ----------------------- diff --git "a/problems/0198.346円211円223円345円256円266円345円212円253円350円210円215円.md" "b/problems/0198.346円211円223円345円256円266円345円212円253円350円210円215円.md" index dfe1f3a062..a828b9a9d6 100644 --- "a/problems/0198.346円211円223円345円256円266円345円212円253円350円210円215円.md" +++ "b/problems/0198.346円211円223円345円256円266円345円212円253円350円210円215円.md" @@ -189,6 +189,29 @@ const rob = nums => { }; ``` +TypeScript: + +```typescript +function rob(nums: number[]): number { + /** + dp[i]: 前i个房屋能偷到的最大金额 + dp[0]: nums[0]; + dp[1]: max(nums[0], nums[1]); + ... + dp[i]: max(dp[i-1], dp[i-2]+nums[i]); + */ + const length: number = nums.length; + if (length === 1) return nums[0]; + const dp: number[] = []; + dp[0] = nums[0]; + dp[1] = Math.max(nums[0], nums[1]); + for (let i = 2; i < length; i++) { + dp[i] = Math.max(dp[i - 1], dp[i - 2] + nums[i]); + } + return dp[length - 1]; +}; +``` + diff --git "a/problems/0209.351円225円277円345円272円246円346円234円200円345円260円217円347円232円204円345円255円220円346円225円260円347円273円204円.md" "b/problems/0209.351円225円277円345円272円246円346円234円200円345円260円217円347円232円204円345円255円220円346円225円260円347円273円204円.md" index d31cba3fab..fbef7692cd 100644 --- "a/problems/0209.351円225円277円345円272円246円346円234円200円345円260円217円347円232円204円345円255円220円346円225円260円347円273円204円.md" +++ "b/problems/0209.351円225円277円345円272円246円346円234円200円345円260円217円347円232円204円345円255円220円346円225円260円347円273円204円.md" @@ -400,6 +400,54 @@ class Solution { } } ``` +Scala: + +滑动窗口: +```scala +object Solution { + def minSubArrayLen(target: Int, nums: Array[Int]): Int = { + var result = Int.MaxValue // 返回结果,默认最大值 + var left = 0 // 慢指针,当sum>=target,向右移动 + var sum = 0 // 窗口值的总和 + for (right <- 0 until nums.length) { + sum += nums(right) + while (sum>= target) { + result = math.min(result, right - left + 1) // 产生新结果 + sum -= nums(left) // 左指针移动,窗口总和减去左指针的值 + left += 1 // 左指针向右移动 + } + } + // 相当于三元运算符,return关键字可以省略 + if (result == Int.MaxValue) 0 else result + } +} +``` + +暴力解法: +```scala +object Solution { + def minSubArrayLen(target: Int, nums: Array[Int]): Int = { + import scala.util.control.Breaks + var res = Int.MaxValue + var subLength = 0 + for (i <- 0 until nums.length) { + var sum = 0 + Breaks.breakable( + for (j <- i until nums.length) { + sum += nums(j) + if (sum>= target) { + subLength = j - i + 1 + res = math.min(subLength, res) + Breaks.break() + } + } + ) + } + // 相当于三元运算符 + if (res == Int.MaxValue) 0 else res + } +} +``` -----------------------
diff --git "a/problems/0213.346円211円223円345円256円266円345円212円253円350円210円215円II.md" "b/problems/0213.346円211円223円345円256円266円345円212円253円350円210円215円II.md" index 8e569e46cf..9e698d01c0 100644 --- "a/problems/0213.346円211円223円345円256円266円345円212円253円350円210円215円II.md" +++ "b/problems/0213.346円211円223円345円256円266円345円212円253円350円210円215円II.md" @@ -165,7 +165,30 @@ const robRange = (nums, start, end) => { return dp[end] } ``` +TypeScript: + +```typescript +function rob(nums: number[]): number { + const length: number = nums.length; + if (length === 0) return 0; + if (length === 1) return nums[0]; + return Math.max(robRange(nums, 0, length - 2), + robRange(nums, 1, length - 1)); +}; +function robRange(nums: number[], start: number, end: number): number { + if (start === end) return nums[start]; + const dp: number[] = []; + dp[start] = nums[start]; + dp[start + 1] = Math.max(nums[start], nums[start + 1]); + for (let i = start + 2; i <= end; i++) { + dp[i] = Math.max(dp[i - 1], dp[i - 2] + nums[i]); + } + return dp[end]; +} +``` + Go: + ```go // 打家劫舍II 动态规划 // 时间复杂度O(n) 空间复杂度O(n) diff --git "a/problems/0416.345円210円206円345円211円262円347円255円211円345円222円214円345円255円220円351円233円206円.md" "b/problems/0416.345円210円206円345円211円262円347円255円211円345円222円214円345円255円220円351円233円206円.md" index 61565bc277..eb6601e184 100644 --- "a/problems/0416.345円210円206円345円211円262円347円255円211円345円222円214円345円255円220円351円233円206円.md" +++ "b/problems/0416.345円210円206円345円211円262円347円255円211円345円222円214円345円255円220円351円233円206円.md" @@ -416,6 +416,108 @@ 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; +} +``` + TypeScript: > 一维数组,简洁 diff --git "a/problems/0701.344円272円214円345円217円211円346円220円234円347円264円242円346円240円221円344円270円255円347円232円204円346円217円222円345円205円245円346円223円215円344円275円234円.md" "b/problems/0701.344円272円214円345円217円211円346円220円234円347円264円242円346円240円221円344円270円255円347円232円204円346円217円222円345円205円245円346円223円215円344円275円234円.md" index df6a395444..50e39ade5e 100644 --- "a/problems/0701.344円272円214円345円217円211円346円220円234円347円264円242円346円240円221円344円270円255円347円232円204円346円217円222円345円205円245円346円223円215円344円275円234円.md" +++ "b/problems/0701.344円272円214円345円217円211円346円220円234円347円264円242円346円240円221円344円270円255円347円232円204円346円217円222円345円205円245円346円223円215円344円275円234円.md" @@ -279,7 +279,7 @@ class Solution: root.right = self.insertIntoBST(root.right, val) # 返回更新后的以当前root为根节点的新树 - return roo + return root ``` **递归法** - 无返回值 diff --git "a/problems/0977.346円234円211円345円272円217円346円225円260円347円273円204円347円232円204円345円271円263円346円226円271円.md" "b/problems/0977.346円234円211円345円272円217円346円225円260円347円273円204円347円232円204円345円271円263円346円226円271円.md" index 24276bcff0..0e79a3d654 100644 --- "a/problems/0977.346円234円211円345円272円217円346円225円260円347円273円204円347円232円204円345円271円263円346円226円271円.md" +++ "b/problems/0977.346円234円211円345円272円217円346円225円260円347円273円204円347円232円204円345円271円263円346円226円271円.md" @@ -358,7 +358,41 @@ class Solution { } } ``` - +Scala: + +双指针: +```scala +object Solution { + def sortedSquares(nums: Array[Int]): Array[Int] = { + val res: Array[Int] = new Array[Int](nums.length) + var top = nums.length - 1 + var i = 0 + var j = nums.length - 1 + while (i <= j) { + if (nums(i) * nums(i) <= nums(j) * nums(j)) { + // 当左侧平方小于等于右侧,res数组顶部放右侧的平方,并且top下移,j左移 + res(top) = nums(j) * nums(j) + top -= 1 + j -= 1 + } else { + // 当左侧平方大于右侧,res数组顶部放左侧的平方,并且top下移,i右移 + res(top) = nums(i) * nums(i) + top -= 1 + i += 1 + } + } + res + } +} +``` +骚操作(暴力思路): +```scala +object Solution { + def sortedSquares(nums: Array[Int]): Array[Int] = { + nums.map(x=>{x*x}).sortWith(_ < _) + } +} +``` ----------------------- diff --git "a/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-1.md" "b/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-1.md" index 36daffcf03..d2ab191aaf 100644 --- "a/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-1.md" +++ "b/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-1.md" @@ -432,6 +432,54 @@ 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; +} +``` + + ### TypeScript ```typescript diff --git "a/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-2.md" "b/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-2.md" index 155c98e038..b66b74a671 100644 --- "a/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-2.md" +++ "b/problems/350円203円214円345円214円205円347円220円206円350円256円272円345円237円272円347円241円20001円350円203円214円345円214円205円-2.md" @@ -317,6 +317,40 @@ 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; +} +``` + ### TypeScript ```typescript diff --git "a/problems/350円203円214円345円214円205円351円227円256円351円242円230円347円220円206円350円256円272円345円237円272円347円241円200円345円244円232円351円207円215円350円203円214円345円214円205円.md" "b/problems/350円203円214円345円214円205円351円227円256円351円242円230円347円220円206円350円256円272円345円237円272円347円241円200円345円244円232円351円207円215円350円203円214円345円214円205円.md" index a988db2c82..712380f4f4 100644 --- "a/problems/350円203円214円345円214円205円351円227円256円351円242円230円347円220円206円350円256円272円345円237円272円347円241円200円345円244円232円351円207円215円350円203円214円345円214円205円.md" +++ "b/problems/350円203円214円345円214円205円351円227円256円351円242円230円347円220円206円350円256円272円345円237円272円347円241円200円345円244円232円351円207円215円350円203円214円345円214円205円.md" @@ -334,6 +334,64 @@ func Test_multiplePack(t *testing.T) { PASS ``` +TypeScript: + +> 版本一(改变数据源): + +```typescript +function testMultiPack() { + const bagSize: number = 10; + const weightArr: number[] = [1, 3, 4], + valueArr: number[] = [15, 20, 30], + amountArr: number[] = [2, 3, 2]; + for (let i = 0, length = amountArr.length; i < length; i++) { + while (amountArr[i]> 1) { + weightArr.push(weightArr[i]); + valueArr.push(valueArr[i]); + amountArr[i]--; + } + } + const goodsNum: number = weightArr.length; + const dp: number[] = new Array(bagSize + 1).fill(0); + // 遍历物品 + for (let i = 0; i < goodsNum; i++) { + // 遍历背包容量 + for (let j = bagSize; j>= weightArr[i]; j--) { + dp[j] = Math.max(dp[j], dp[j - weightArr[i]] + valueArr[i]); + } + } + console.log(dp); +} +testMultiPack(); +``` + +> 版本二(改变遍历方式): + +```typescript +function testMultiPack() { + const bagSize: number = 10; + const weightArr: number[] = [1, 3, 4], + valueArr: number[] = [15, 20, 30], + amountArr: number[] = [2, 3, 2]; + const goodsNum: number = weightArr.length; + const dp: number[] = new Array(bagSize + 1).fill(0); + // 遍历物品 + for (let i = 0; i < goodsNum; i++) { + // 遍历物品个数 + for (let j = 0; j < amountArr[i]; j++) { + // 遍历背包容量 + for (let k = bagSize; k>= weightArr[i]; k--) { + dp[k] = Math.max(dp[k], dp[k - weightArr[i]] + valueArr[i]); + } + } + } + console.log(dp); +} +testMultiPack(); +``` + + + -----------------------

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