34. Find First and Last Position of Element in Sorted Array
Given an array of integers nums
sorted in ascending order, find the starting and ending position of a given target
value.
Your algorithm's runtime complexity must be in the order of O(log n).
If the target is not found in the array, return [-1, -1]
.
Example 1:
Input: nums = [5,7,7,8,8,10]
, target = 8
Output: [3,4]
Example 2:
Input: nums = [5,7,7,8,8,10]
, target = 6 Output: [-1,-1]
题意:给定一个排好序的数字数组,返回匹配到target的第一项和第二项的索引
代码如下:
/** * @param {number[]} nums * @param {number} target * @return {number[]} */ var searchRange = function(nums, target) { var res=[]; var count=0; for(var i=0;i<nums.length;i++){ if(nums[i]===target){ res.push(i);count++; break;} } for(var i=nums.length-1;i>=0;i--){ if(nums[i]===target) {res.push(i);count++; break;} } if(count==2) return res; return [-1,-1] };