Search Insert Position

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.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

思路：

二分查找，找到i、j位置，如果i>j，返回i即可。

代码：

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int length=nums.size();
        int i=0,j=length-1;

        if(nums[0]>target){
            return 0;
        }

        if(nums[length-1]<target){
            return length;
        }
        while(i<=j){
            int mid=(i+j)/2;
            if(nums[mid]==target){
                return mid;
            }
            if(nums[mid]<target){
                i=mid+1;
            }
            if(nums[mid]>target){
                j=mid-1;
            }
        }

        if(i>j){
            return i;
        }
    }
};