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

改良版二分法，找到返回，找不到返回终止条件开始加1.

class Solution {
public:
    int search(int A[], int start, int end, int target) {
        if (start > end) return start;
        int mid = (start + end) / 2;
        if (A[mid] == target) return mid;
        else if (A[mid] > target) return search(A, start, mid - 1, target);
        else return search(A, mid + 1, end, target);
    }
int searchInsert(int A[], int n, int target) {
        return search(A, 0, n - 1, target);
    }
};