leetcode 035 Search Insert Position

最新推荐文章于 2019-05-31 00:39:10 发布

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本文介绍了一个算法问题：在已排序的数组中查找目标值的索引，若不存在则返回目标值按序插入的位置。该算法使用了二分查找的方法来高效定位目标值或其合适的插入位置。

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

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#include <iostream>
#include <cstdio>
#include <string>
using namespace std;

class Solution {
public:
	int searchInsert(vector<int>& nums, int target) {
		int l = 0, r = nums.size()-1, pos=-1;

		while(l <= r) {
			int mid = (l+r)/2;

			if(nums[mid] == target) {
				pos = mid;
				break;
			} else if(nums[mid] > target) {
				r = mid-1;
			} else {
				l = mid+1;
			}
		}

		if(l <= r) return pos;

		else return l;
	}
}