34. Find First and Last Position of Element in Sorted Array

⭐⭐⭐

題目敘述

Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value.

If target is not found in the array, return [-1, -1].

You must write an algorithm with O(log n) runtime complexity.

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]

Example 3

Input: nums = [], target = 0 Output: [-1,-1]

解題思路

Solution

class Solution {
    public int[] searchRange(int[] nums, int target) {
        int[] ans = {-1, -1};

        for(int i = 0; i < nums.length; i++){
            if(target == nums[i] && ans[0] == -1){
                ans[0] = i;
            }
            if(target == nums[i]){
                ans[1] = Math.max(ans[1], i);
            }
        }

        return ans;
    }
}