LeetCode之Search Insert Position

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

题目解析：在有序数组中查找元素，找得到就返回位置，找不到就返回应该插入的位置。

思路：二分搜索，找不到的时候返回左边的指针即可(代码中的ll)即可，代码如下：

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