LeetCode - 35. Search Insert Position【二分查找】

题目

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

题意

输入有序数组和一个数，要求输出该数有序插入到该数组中的位置；如果数组中存在该数，直接输出该数在数组中的位置。

分析

最基本的二分查找。

代码

class Solution{
public:
	int searchInsert(vet<int> & str, target) {
		int l = -1, r = str.size();
		while(r - l > 0) {
			int mid = (r - l) / 2;
			if(str[mid] >= target）	r = mid; 
			else	l = mid;
		}
		return r;
	}
};