算法

Author: dddssw

javascript/algorithm.md

@@ -1127,4 +1127,54 @@ var findDuplicate = function (nums) {
 };
 // o(n)
 // o(1)
-```
+```
+
+## 二分查找
+### [搜索插入位置](https://leetcode.cn/problems/search-insert-position/description/?envType=study-plan-v2&envId=top-100-liked)
+```js
+var searchInsert = function (nums, target) {
+  let left = 0;
+  let right = nums.length - 1;
+  while (left <= right) {
+    let mid = Math.floor((left + right) / 2);
+    if (nums[mid] === target) {
+      return mid;
+    }
+    if (target < nums[mid]) {
+      right = mid - 1;
+    } else {
+      left = mid + 1;
+    }
+  }
+  return left;
+};
+```
+### [搜索旋转排序数组](https://leetcode.cn/problems/search-in-rotated-sorted-array/description/)
+每次二分后，子数组 [left, mid] 或 [mid, right] ​​至少有一个是有序的
+```js
+var search = function (nums, target) {
+  let left = 0;
+  let right = nums.length - 1;
+  while (left <= right) {//子数组长度为 1
+    let mid = Math.floor((left + right) / 2);
+    if (nums[mid] === target) {
+      return mid;
+    }
+    if (nums[left] <= nums[mid]) {//不加=会以为右边是有序的
+      if (target >= nums[left] && target <= nums[mid]) {
+        right = mid - 1;
+      } else {
+        left = mid + 1;
+      }
+    } else {
+      if (target >= nums[mid] && target <= nums[right]) {
+        left = mid + 1;
+      } else {
+        right = mid - 1;
+      }
+    }
+  }
+  return -1;
+};
+```
+## 快速排序