[LeetCode] 35. Search Insert Position

题目链接: https://leetcode.com/problems/search-insert-position/

Description

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

解题思路

就是二分查找，每次取半，若中间的正好是

target

则返回

mid

;　若中间的数大于

target

，则继续在右边一半查找；否则，在左边一半查找。

Code

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