Search Insert Position

题目描述

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.
You may assume no duplicates in the array.
Here are few examples.
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

题目解答

解题思路

可以使用二分法来解决这个题目，返回的结果为middle或者left
因为循环结束的时候left > right , 所以返回left

实现代码

public class Solution {
    public int searchInsert(int[] nums, int target) {
        if(nums.length == 0)
            return 0;
        int left = 0;
        int right = nums.length - 1;
        while(left <= right){
            int middle = (left + right) / 2;
            if(nums[middle] == target){
                return middle;
            }else if(nums[middle] > target){
                right = middle - 1;
            }else {
                left = middle + 1;
            }
        }
        return left;
    }
}