Merge branch 'master' of https://github.com/youngyangyang04/leetcode

problems/0015.三数之和.md

@@ -218,8 +218,33 @@ class Solution {
 ```
 
 Python：
-
-
+```Python
+class Solution:
+    def threeSum(self, nums):
+        ans = []
+        n = len(nums)
+        nums.sort()
+        for i in range(n):
+            left = i + 1
+            right = n - 1
+            if nums[i] > 0:
+                break
+            if i >= 1 and nums[i] == nums[i - 1]:
+                continue
+            while left < right:
+                total = nums[i] + nums[left] + nums[right]
+                if total > 0:
+                    right -= 1
+                elif total < 0:
+                    left += 1
+                else:
+                    ans.append([nums[i], nums[left], nums[right]])
+                    while left != right and nums[left] == nums[left + 1]: left += 1
+                    while left != right and nums[right] == nums[right - 1]: right -= 1
+                    left += 1
+                    right -= 1
+        return ans
+```
 Go：
 ```Go
 func threeSum(nums []int)[][]int{
@@ -256,6 +281,59 @@ func threeSum(nums []int)[][]int{
 }
 ```
 
+javaScript: 
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+
+// 循环内不考虑去重 
+var threeSum = function(nums) {
+    const len = nums.length;
+    if(len < 3) return [];
+    nums.sort((a, b) => a - b);
+    const resSet = new Set();
+    for(let i = 0; i < len - 2; i++) {
+        if(nums[i] > 0) break;
+        let l = i + 1, r = len - 1;
+        while(l < r) {
+            const sum = nums[i] + nums[l] + nums[r];
+            if(sum < 0) { l++; continue };
+            if(sum > 0) { r--; continue };
+            resSet.add(`${nums[i]},${nums[l]},${nums[r]}`);
+            l++;
+            r--;
+        }
+    }
+    return Array.from(resSet).map(i => i.split(","));
+};
+
+// 去重优化
+var threeSum = function(nums) {
+    const len = nums.length;
+    if(len < 3) return [];
+    nums.sort((a, b) => a - b);
+    const res = [];
+    for(let i = 0; i < len - 2; i++) {
+        if(nums[i] > 0) break;
+        // a去重
+        if(i > 0 && nums[i] === nums[i - 1]) continue;
+        let l = i + 1, r = len - 1;
+        while(l < r) {
+            const sum = nums[i] + nums[l] + nums[r];
+            if(sum < 0) { l++; continue };
+            if(sum > 0) { r--; continue };
+            res.push([nums[i], nums[l], nums[r]])
+            // b c 去重 
+            while(l < r && nums[l] === nums[++l]);
+            while(l < r && nums[r] === nums[--r]);
+        }
+    }
+    return res;
+};
+```
 
 
 

problems/0018.四数之和.md

@@ -165,11 +165,75 @@ class Solution {
 ```
 
 Python：
-
+```python
+
+class Solution(object):
+    def fourSum(self, nums, target):
+        """
+        :type nums: List[int]
+        :type target: int
+        :rtype: List[List[int]]
+        """
+        # use a dict to store value:showtimes
+        hashmap = dict()
+        for n in nums:
+            if n in hashmap:
+                hashmap[n] += 1
+            else: 
+                hashmap[n] = 1
+
+        # good thing about using python is you can use set to drop duplicates.
+        ans = set()
+        for i in range(len(nums)):
+            for j in range(i + 1, len(nums)):
+                for k in range(j + 1, len(nums)):
+                    val = target - (nums[i] + nums[j] + nums[k])
+                    if val in hashmap:
+                        # make sure no duplicates.
+                        count = (nums[i] == val) + (nums[j] == val) + (nums[k] == val)
+                        if hashmap[val] > count:
+                            ans.add(tuple(sorted([nums[i], nums[j], nums[k], val])))
+                    else:
+                        continue
+        return ans
+
+```
 
 Go：
 
-
+javaScript: 
+
+```js
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[][]}
+ */
+var fourSum = function(nums, target) {
+    const len = nums.length;
+    if(len < 4) return [];
+    nums.sort((a, b) => a - b);
+    const res = [];
+    for(let i = 0; i < len - 3; i++) {
+        // 去重i
+        if(i > 0 && nums[i] === nums[i - 1]) continue;
+        for(let j = i + 1; j < len - 2; j++) {
+            // 去重j
+            if(j > i + 1 && nums[j] === nums[j - 1]) continue;
+            let l = j + 1, r = len - 1;
+            while(l < r) {
+                const sum = nums[i] + nums[j] + nums[l] + nums[r];
+                if(sum < target) { l++; continue}
+                if(sum > target) { r--; continue}
+                res.push([nums[i], nums[j], nums[l], nums[r]]);
+                while(l < r && nums[l] === nums[++l]);
+                while(l < r && nums[r] === nums[--r]);
+            }
+        } 
+    }
+    return res;
+};
+```
 
 
 -----------------------

problems/0056.合并区间.md

@@ -168,15 +168,54 @@ class Solution {
 ```
 
 Python：
-
+```python
+class Solution:
+    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
+        if len(intervals) == 0: return intervals
+        intervals.sort(key=lambda x: x[0])
+        result = []
+        result.append(intervals[0])
+        for i in range(1, len(intervals)):
+            last = result[-1]
+            if last[1] >= intervals[i][0]:
+                result[-1] = [last[0], max(last[1], intervals[i][1])]
+            else:
+                result.append(intervals[i])
+        return result
+```
 
 Go：
-
+```Go
+func merge(intervals [][]int) [][]int {
+	sort.Slice(intervals, func(i, j int) bool {
+		return intervals[i][0]<intervals[j][0]
+	})
+
+	res:=[][]int{}
+	prev:=intervals[0]
+
+	for i:=1;i<len(intervals);i++{
+		cur :=intervals[i]
+		if prev[1]<cur[0]{
+			res=append(res,prev)
+			prev=cur
+		}else {
+			prev[1]=max(prev[1],cur[1])
+		}
+	}
+	res=append(res,prev)
+	return res
+}
+func max(a, b int) int {
+	if a > b { return a }
+	return b
+}
+```
 
 
 
 -----------------------
 * 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/0059.螺旋矩阵II.md

@@ -224,6 +224,49 @@ class Solution:
         return matrix
 ```
 
+javaScript
+
+```js
+
+/**
+ * @param {number} n
+ * @return {number[][]}
+ */
+var generateMatrix = function(n) {
+    // new Array(n).fill(new Array(n))
+    // 使用fill --> 填充的是同一个数组地址
+    const res = Array.from({length: n}).map(() => new Array(n));
+    let loop = n >> 1, i = 0, //循环次数
+        count = 1,
+        startX = startY = 0; // 起始位置 
+    while(++i <= loop) {
+        // 定义行列
+        let row = startX, column = startY;
+        // [ startY, n - i)
+        while(column < n - i) {
+            res[row][column++] = count++;
+        }
+        // [ startX, n - i)
+        while(row < n - i) {
+            res[row++][column] = count++;
+        }
+        // [n - i ,  startY)
+        while(column > startY) {
+            res[row][column--] = count++; 
+        }
+        // [n - i ,  startX)
+        while(row > startX) {
+            res[row--][column] = count++;
+        }
+        startX = ++startY;
+    }
+    if(n & 1) {
+        res[startX][startY] = count;
+    }
+    return res;
+};
+```
+
 
 
 -----------------------

problems/0062.不同路径.md

@@ -249,7 +249,24 @@ Python：
 
 
 Go：
-
+```Go
+func uniquePaths(m int, n int) int {
+	dp := make([][]int, m)
+	for i := range dp {
+		dp[i] = make([]int, n)
+		dp[i][0] = 1
+	}
+	for j := 0; j < n; j++ {
+		dp[0][j] = 1
+	}
+	for i := 1; i < m; i++ {
+		for j := 1; j < n; j++ {
+			dp[i][j] = dp[i-1][j] + dp[i][j-1]
+		}
+	}
+	return dp[m-1][n-1]
+}
+```