文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. 问题描述

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.

Example 1:

Input: [1,3,5,6], 5
Output: 2

Example 2:

Input: [1,3,5,6], 2
Output: 1

Example 3:

Input: [1,3,5,6], 7
Output: 4

Example 4:

Input: [1,3,5,6], 0
Output: 0

2. 求解

Solution(C++):

这道题就是一个二分查找问题。

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