Merge branch 'master' into patch-29

problems/0070.爬楼梯完全背包版本.md

@@ -146,19 +146,24 @@ class Solution {
 ```
 
 Python：
-```python
+
+
+```python3
 class Solution:
     def climbStairs(self, n: int) -> int:
-        m = 2
+        dp = [0]*(n + 1)
-        dp = [0] * (n + 1)
         dp[0] = 1
-        for i in range(n + 1):
+        m = 2
-            for j in range(1, m + 1):
+        # 遍历背包
-                if i >= j:
+        for j in range(n + 1):
-                    dp[i] += dp[i - j]
+            # 遍历物品
-        return dp[-1]
+            for step in range(1, m + 1):
+                if j >= step:
+                    dp[j] += dp[j - step]
+        return dp[n]
 ```
 
+
 Go：
 ```go
 func climbStairs(n int) int {

problems/0072.编辑距离.md

@@ -228,7 +228,22 @@ public int minDistance(String word1, String word2) {
 ```
 
 Python：
-
+```python
+class Solution:
+    def minDistance(self, word1: str, word2: str) -> int:
+        dp = [[0] * (len(word2)+1) for _ in range(len(word1)+1)]
+        for i in range(len(word1)+1):
+            dp[i][0] = i
+        for j in range(len(word2)+1):
+            dp[0][j] = j
+        for i in range(1, len(word1)+1):
+            for j in range(1, len(word2)+1):
+                if word1[i-1] == word2[j-1]:
+                    dp[i][j] = dp[i-1][j-1]
+                else:
+                    dp[i][j] = min(dp[i-1][j-1], dp[i-1][j], dp[i][j-1]) + 1
+        return dp[-1][-1]
+```
 
 Go：
 ```Go

problems/0151.翻转字符串里的单词.md

@@ -183,7 +183,7 @@ public:
         int end = 0; // 反转的单词在字符串里终止位置
         bool entry = false; // 标记枚举字符串的过程中是否已经进入了单词区间
         for (int i = 0; i < s.size(); i++) { // 开始反转单词
-            if ((!entry))) {
+            if (!entry) {
                 start = i; // 确定单词起始位置
                 entry = true; // 进入单词区间
             }
@@ -380,4 +380,4 @@ func reverse(b *[]byte, left, right int) {
 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
 * B站视频：[代码随想录](https://space.bilibili.com/525438321)
 * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
-<div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>
+<div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>

problems/0198.打家劫舍.md

@@ -118,7 +118,7 @@ class Solution {
 		if (nums == null || nums.length == 0) return 0;
 		if (nums.length == 1) return nums[0];
 
-		int[] dp = new int[nums.length + 1];
+		int[] dp = new int[nums.length];
 		dp[0] = nums[0];
 		dp[1] = Math.max(dp[0], nums[1]);
 		for (int i = 2; i < nums.length; i++) {

problems/0322.零钱兑换.md

@@ -226,11 +226,11 @@ func coinChange1(coins []int, amount int) int {
 	for i := 0; i < len(coins); i++ {
 		// 遍历背包
 		for j := coins[i]; j <= amount; j++ {
-			//if dp[j-coins[i]] != math.MaxInt32 {
+			if dp[j-coins[i]] != math.MaxInt32 {
 				// 推导公式
 				dp[j] = min(dp[j], dp[j-coins[i]]+1)
-				fmt.Println(dp,j,i)
+				//fmt.Println(dp,j,i)
-			//}
+			}
 		}
 	}
 	// 没找到能装满背包的, 就返回-1

problems/0392.判断子序列.md

@@ -144,7 +144,20 @@ Java：
 
 
 Python：
-
+```python
+class Solution:
+    def isSubsequence(self, s: str, t: str) -> bool:
+        dp = [[0] * (len(t)+1) for _ in range(len(s)+1)]
+        for i in range(1, len(s)+1):
+            for j in range(1, len(t)+1):
+                if s[i-1] == t[j-1]:
+                    dp[i][j] = dp[i-1][j-1] + 1
+                else:
+                    dp[i][j] = dp[i][j-1]
+        if dp[-1][-1] == len(s):
+            return True
+        return False
+```
 
 Go：
 

problems/0516.最长回文子序列.md

@@ -170,7 +170,20 @@ public class Solution {
 
 
 Python：
-
+```python
+class Solution:
+    def longestPalindromeSubseq(self, s: str) -> int:
+        dp = [[0] * len(s) for _ in range(len(s))]
+        for i in range(len(s)):
+            dp[i][i] = 1
+        for i in range(len(s)-1, -1, -1):
+            for j in range(i+1, len(s)):
+                if s[i] == s[j]:
+                    dp[i][j] = dp[i+1][j-1] + 2
+                else:
+                    dp[i][j] = max(dp[i+1][j], dp[i][j-1])
+        return dp[0][-1]
+```
 
 Go：
 ```Go

problems/0583.两个字符串的删除操作.md

@@ -107,7 +107,22 @@ Java：
 
 
 Python：
-
+```python
+class Solution:
+    def minDistance(self, word1: str, word2: str) -> int:
+        dp = [[0] * (len(word2)+1) for _ in range(len(word1)+1)]
+        for i in range(len(word1)+1):
+            dp[i][0] = i
+        for j in range(len(word2)+1):
+            dp[0][j] = j
+        for i in range(1, len(word1)+1):
+            for j in range(1, len(word2)+1):
+                if word1[i-1] == word2[j-1]:
+                    dp[i][j] = dp[i-1][j-1]
+                else:
+                    dp[i][j] = min(dp[i-1][j-1] + 2, dp[i-1][j] + 1, dp[i][j-1] + 1)
+        return dp[-1][-1]
+```
 
 Go：
 

problems/0647.回文子串.md

@@ -284,6 +284,56 @@ class Solution {
 
 Python：
 
+> 动态规划：
+```python
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        dp = [[False] * len(s) for _ in range(len(s))]
+        result = 0
+        for i in range(len(s)-1, -1, -1): #注意遍历顺序
+            for j in range(i, len(s)):
+                if s[i] == s[j]:
+                    if j - i <= 1: #情况一 和 情况二
+                        result += 1
+                        dp[i][j] = True
+                    elif dp[i+1][j-1]: #情况三
+                        result += 1
+                        dp[i][j] = True
+        return result
+```
+
+> 动态规划：简洁版
+```python
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        dp = [[False] * len(s) for _ in range(len(s))]
+        result = 0
+        for i in range(len(s)-1, -1, -1): #注意遍历顺序
+            for j in range(i, len(s)):
+                if s[i] == s[j] and (j - i <= 1 or dp[i+1][j-1]): 
+                    result += 1
+                    dp[i][j] = True
+        return result
+```
+
+> 双指针法：
+```python
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        result = 0
+        for i in range(len(s)):
+            result += self.extend(s, i, i, len(s)) #以i为中心
+            result += self.extend(s, i, i+1, len(s)) #以i和i+1为中心
+        return result
+    
+    def extend(self, s, i, j, n):
+        res = 0
+        while i >= 0 and j < n and s[i] == s[j]:
+            i -= 1
+            j += 1
+            res += 1
+        return res
+```
 
 Go：
 ```Go

problems/0739.每日温度.md

@@ -180,7 +180,36 @@ public:
 
 
 Java：
-
+```java
+/**
+     * 单调栈，栈内顺序要么从大到小 要么从小到大,本题从大到笑
+     * <p>
+     * 入站元素要和当前栈内栈首元素进行比较
+     * 若大于栈首则 则与元素下标做差
+     * 若大于等于则放入
+     *
+     * @param temperatures
+     * @return
+     */
+    public static int[] dailyTemperatures(int[] temperatures) {
+        Stack<Integer> stack = new Stack<>();
+        int[] res = new int[temperatures.length];
+        for (int i = 0; i < temperatures.length; i++) {
+            /**
+             * 取出下标进行元素值的比较
+             */
+            while (!stack.isEmpty() && temperatures[i] > temperatures[stack.peek()]) {
+                int preIndex = stack.pop();
+                res[preIndex] = i - preIndex;
+            }
+            /**
+             * 注意 放入的是元素位置
+             */
+            stack.push(i);
+        }
+        return res;
+    }
+```
 Python：
 
 Go：

problems/0977.有序数组的平方.md

@@ -96,8 +96,46 @@ public:
 
 ## 其他语言版本
 
-
 Java：
+```Java
+class Solution {
+    public int[] sortedSquares(int[] nums) {
+        int right = nums.length - 1;
+        int left = 0;
+        int[] result = new int[nums.length];
+        int index = result.length - 1;
+        while (left <= right) {
+            if (nums[left] * nums[left] > nums[right] * nums[right]) {
+                result[index--] = nums[left] * nums[left];
+                ++left;
+            } else {
+                result[index--] = nums[right] * nums[right];
+                --right;
+            }
+        }
+        return result;
+    }
+}
+```
+
+```java
+class Solution {
+    public int[] sortedSquares(int[] nums) {
+        int l = 0;
+        int r = nums.length - 1;
+        int[] res = new int[nums.length];
+        int j = nums.length - 1;
+        while(l <= r){
+            if(nums[l] * nums[l] > nums[r] * nums[r]){
+                res[j--] = nums[l] * nums[l++];
+            }else{
+                res[j--] = nums[r] * nums[r--];
+            }
+        }
+        return res;
+    }
+}
+```
 
 Python：
 ```Python

problems/1005.K次取反后最大化的数组和.md

@@ -133,7 +133,7 @@ class Solution:
                 A[i] *= -1
                 K -= 1
         if K > 0:
-            A[len(A) - 1] *= ((-1)**K)
+            A[-1] *= (-1)**K #取A最后一个数只需要写-1
         return sum(A)
 ```