新增34.朴实无华的二分查找 JavaScript版本

This commit is contained in:
jerryfishcode
2021-09-27 21:34:56 +08:00
committed by GitHub
parent 66b3cac2c7
commit f34b247264

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@ -396,6 +396,46 @@ class Solution:
## JavaScript
```js
var searchRange = function(nums, target) {
const getLeftBorder = (nums, target) => {
let left = 0, right = nums.length - 1;
let leftBorder = -2;// 记录一下leftBorder没有被赋值的情况
while(left <= right){
let middle = left + ((right - left) >> 1);
if(nums[middle] >= target){ // 寻找左边界nums[middle] == target的时候更新right
right = middle - 1;
leftBorder = right;
} else {
left = middle + 1;
}
}
return leftBorder;
}
const getRightBorder = (nums, target) => {
let left = 0, right = nums.length - 1;
let rightBorder = -2; // 记录一下rightBorder没有被赋值的情况
while (left <= right) {
let middle = left + ((right - left) >> 1);
if (nums[middle] > target) {
right = middle - 1;
} else { // 寻找右边界nums[middle] == target的时候更新left
left = middle + 1;
rightBorder = left;
}
}
return rightBorder;
}
let leftBorder = getLeftBorder(nums, target);
let rightBorder = getRightBorder(nums, target);
// 情况一
if(leftBorder === -2 || rightBorder === -2) return [-1,-1];
// 情况三
if (rightBorder - leftBorder > 1) return [leftBorder + 1, rightBorder - 1];
// 情况二
return [-1, -1];
};
```
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