Search Insert Position -LeetCode

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

1、数组有序，直接查找，O(n)

int searchInsert(int A[], int n, int target) {                for(int i=0;i<n;i++)        {            if(A[i]>=target) return i;        }                return n;    }

2、二分查找-非递归 O(log n)

int searchInsert(int A[], int n, int target) {                if(A[0]>=target) return 0;        if(A[n-1]<target) return n;                int low=1;         int high=n-1;        int mid=0;        while(low<=high)        {            mid=(low+high)/2;                        if(A[mid]==target) return mid;            if(A[mid]>target)            {                high=mid-1;            }            else             low=mid+1;        }        return low;    }