[LeetCode] 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.

 

这里要考虑清楚为什么要返回left。

int findPos(int A[], int left, int right, int target) {
    if (left > right) return left;
    int mid = (left + right) /2;
    if (target > A[mid]) {
        return findPos(A, mid+1, right, target);
    }
    else if (target < A[mid]) {
        return findPos(A, left, mid-1, target);
    }
    else {
        return mid;
    }
}

int searchInsert(int A[], int n, int target) {
    if (n == 0) return 0;
    return findPos(A, 0, n-1, target);
}