Merge branch 'master' of https://github.com/azl397985856/leetcode

91/binary-search.md

@@ -544,6 +544,66 @@ def bisect_left(A, x):
     return l
 ```
 
+##### Java
+
+```java
+import java.util.*;
+public class BinarySearch {
+    public int getPos(int[] A, int val) {
+        int low=0,high=A.lenght-1;
+        while (low <= high){
+            int mid = (low + high)/2;
+            if (A[mid] >= val) {
+                high = mid-1;
+            } else {
+	    	low = mid+1;
+	    } 
+        }
+        return low;
+    }
+}
+```
+
+##### C++
+
+```cpp
+public:
+     int binarySearch(int* arr, int arrLen,int a) {
+        int left = 0;
+        int right = arrLen - 1;
+        while(left<=right)
+        {
+            int mid = (left+right)/2;
+            if(arr[mid]>=a)
+                right = mid - 1;
+            else
+                left = mid + 1;
+        }  
+        return left;
+    }
+```
+
+##### JavaScript
+
+```js
+function binarySearch(nums, target) {
+  let left = 0;
+  let right = nums.length - 1;
+  while (left <= right) {
+    const mid = Math.floor(left + (right - left) / 2);
+    if (nums[mid] >= target) {
+    	// 搜索区间变为 [left, mid-1]
+    	right = mid - 1;
+    }
+    else {
+    	// 搜索区间变为 [mid+1, right]
+    	left = mid + 1;
+    }
+  }
+  return left;
+}
+```
+
 其他语言暂时空缺，欢迎
 [PR](https://github.com/azl397985856/leetcode-cheat/issues/4)
 
@@ -588,6 +648,67 @@ def bisect_right(A, x):
         else: r = mid - 1
     return l # 或者返回 r + 1
 ```
+##### Java
+
+```java
+import java.util.*;
+public class BinarySearch {
+    public int getPos(int[] A, int val) {
+        int low=0,high=A.lenght-1;
+        while (low <= high){
+            int mid = (low + high)/2;
+            if (A[mid] <= val) {
+                low = mid + 1;
+            } else {
+	    	high = mid - 1;
+	    } 
+        }
+        return low;
+    }
+}
+```
+
+##### C++
+
+```cpp
+public:
+     int binarySearch(int* arr, int arrLen,int a) {
+        int left = 0;
+        int right = arrLen - 1;
+        while(left<=right)
+        {
+            int mid = (left+right)/2;
+            if(arr[mid]<=a)
+	    	// 搜索区间变为 [mid+1, right]
+                left = mid + 1;
+            else
+	    	// 搜索区间变为 [left, mid-1]
+                right = mid - 1;
+        }  
+        return left;
+    }
+```
+
+##### JavaScript
+
+```js
+function binarySearch(nums, target) {
+  let left = 0;
+  let right = nums.length - 1;
+  while (left <= right) {
+    const mid = Math.floor(left + (right - left) / 2);
+    if (nums[mid] <= target) {
+    	// 搜索区间变为 [mid+1, right]
+    	left = mid + 1;
+    }
+    else {
+    	// 搜索区间变为 [left, mid-1]
+    	right = mid - 1;
+    }
+  }
+  return left;
+}
+```
 
 其他语言暂时空缺，欢迎
 [PR](https://github.com/azl397985856/leetcode-cheat/issues/4)

problems/1.two-sum.en.md

@@ -29,7 +29,9 @@ The easiest solution to come up with is Brute Force. We could write two for-loop
 
 ## Code
 
-- Support Language: JS
+- Support Language: JS,C++,Java,Python
+
+Javascript Code:
 
 ```js
 /**
@@ -49,6 +51,55 @@ const twoSum = function (nums, target) {
 };
 ```
 
+C++ Code:
+
+```cpp
+class Solution {
+public:
+    vector<int> twoSum(vector<int>& nums, int target) {
+        unordered_map<int, int> hashtable;
+        for (int i = 0; i < nums.size(); ++i) {
+            auto it = hashtable.find(target - nums[i]);
+            if (it != hashtable.end()) {
+                return {it->second, i};
+            }
+            hashtable[nums[i]] = i;
+        }
+        return {};
+    }
+};
+```
+
+Java Code:
+
+```java
+class Solution {
+    public int[] twoSum(int[] nums, int target) {
+        Map<Integer, Integer> hashtable = new HashMap<Integer, Integer>();
+        for (int i = 0; i < nums.length; ++i) {
+            if (hashtable.containsKey(target - nums[i])) {
+                return new int[]{hashtable.get(target - nums[i]), i};
+            }
+            hashtable.put(nums[i], i);
+        }
+        return new int[0];
+    }
+}
+```
+
+Python Code:
+
+```py
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        hashtable = dict()
+        for i, num in enumerate(nums):
+            if target - num in hashtable:
+                return [hashtable[target - num], i]
+            hashtable[nums[i]] = i
+        return []
+```
+
 **_Complexity Anlysis_**
 
 - _Time Complexity_: O(N)

problems/1.two-sum.md

@@ -65,7 +65,7 @@ for(int i = 0; i < n; i++) {
 
 ## 代码
 
-- 语言支持：JS, Go，CPP
+- 语言支持：JS, Go,CPP,Java,Python
 
 ```js
 /**
@@ -119,6 +119,36 @@ public:
 };
 ```
 
+Java Code:
+
+```java
+class Solution {
+    public int[] twoSum(int[] nums, int target) {
+        Map<Integer, Integer> hashtable = new HashMap<Integer, Integer>();
+        for (int i = 0; i < nums.length; ++i) {
+            if (hashtable.containsKey(target - nums[i])) {
+                return new int[]{hashtable.get(target - nums[i]), i};
+            }
+            hashtable.put(nums[i], i);
+        }
+        return new int[0];
+    }
+}
+```
+
+Python Code:
+
+```py
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        hashtable = dict()
+        for i, num in enumerate(nums):
+            if target - num in hashtable:
+                return [hashtable[target - num], i]
+            hashtable[nums[i]] = i
+        return []
+```
+
 **复杂度分析**
 
 - 时间复杂度：$O(N)$

problems/122.best-time-to-buy-and-sell-stock-ii.md

@@ -70,7 +70,7 @@ https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-ii/description/
 
 ## 代码
 
-语言支持：JS，C++，Java
+语言支持：JS，C++，Java，Python
 
 JS Code:
 
@@ -129,6 +129,18 @@ class Solution {
 }
 ```
 
+Python Code:
+
+```py
+class Solution:
+    def maxProfit(self, prices: List[int]) -> int:
+        profit = 0
+        for i in range(1, len(prices)):
+            tmp = prices[i] - prices[i - 1]
+            if tmp > 0: profit += tmp
+        return profit
+```
+
 **复杂度分析**
 
 - 时间复杂度：$O(N)$

problems/125.valid-palindrome.md

@@ -61,7 +61,7 @@ https://leetcode-cn.com/problems/valid-palindrome/description/
 
 ## 代码
 
-- 语言支持：JS，C++，Python
+- 语言支持：JS，C++，Python，Java
 
 JavaScript Code:
 
@@ -160,6 +160,33 @@ class Solution:
         return s == s[::-1]
 ```
 
+Java Code:
+
+```java
+class Solution {
+    public boolean isPalindrome(String s) {
+        int n = s.length();
+        int left = 0, right = n - 1;
+        while (left < right) {
+            while (left < right && !Character.isLetterOrDigit(s.charAt(left))) {
+                ++left;
+            }
+            while (left < right && !Character.isLetterOrDigit(s.charAt(right))) {
+                --right;
+            }
+            if (left < right) {
+                if (Character.toLowerCase(s.charAt(left)) != Character.toLowerCase(s.charAt(right))) {
+                    return false;
+                }
+                ++left;
+                --right;
+            }
+        }
+        return true;
+    }
+}
+```
+
 **复杂度分析**
 
 - 时间复杂度：$O(N)$

problems/169.majority-element.md

@@ -54,7 +54,7 @@ https://leetcode-cn.com/problems/majority-element/
 
 ## 代码
 
-- 语言支持：JS，Python, CPP
+- 语言支持：JS，Python, CPP,Java
 
 Javascript Code:
 
@@ -112,6 +112,26 @@ public:
 };
 ```
 
+Java Code:
+
+```java
+class Solution {
+    public int majorityElement(int[] nums) {
+        int count = 0;
+        Integer candidate = null;
+
+        for (int num : nums) {
+            if (count == 0) {
+                candidate = num;
+            }
+            count += (num == candidate) ? 1 : -1;
+        }
+
+        return candidate;
+    }
+}
+```
+
 **复杂度分析**
 
 - 时间复杂度：$O(N)$，其中 N 为数组长度

problems/190.reverse-bits.md

@@ -75,7 +75,7 @@ eg :
 
 ## 代码
 
-- 语言支持：JS，C++，Python
+- 语言支持：JS，C++，Python，Java
 
 JavaScript Code：
 
@@ -132,6 +132,21 @@ class Solution:
         return ans
 ```
 
+Java Code：
+
+```java
+public class Solution {
+    public int reverseBits(int n) {
+        int rev = 0;
+        for (int i = 0; i < 32 && n != 0; ++i) {
+            rev |= (n & 1) << (31 - i);
+            n >>>= 1;
+        }
+        return rev;
+    }
+}
+```
+
 **复杂度分析**
 
 - 时间复杂度：$O(logN)$