Search Insert Position(lintcode 60)

Description

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.

Example

[1,3,5,6], 5 → 2

[1,3,5,6], 2 → 1

[1,3,5,6], 7 → 4

[1,3,5,6], 0 → 0

Interface

public class Solution {
    /** 
     * param A : an integer sorted array
     * param target :  an integer to be inserted
     * return : an integer
     */
    public int searchInsert(int[] A, int target) {
        // write your code here
    }
}

Solution

public class Solution {
    /** 
     * param A : an integer sorted array
     * param target :  an integer to be inserted
     * return : an integer
     */
    public int searchInsert(int[] A, int target) {
        // write your code here
        if (A == null || A.length == 0) {
            return 0;
        }

        int start = 0;
        int end = A.length - 1;

        while (start + 1 < end) {
            int mid = start + (end - start) / 2;

            if (A[mid] > target) {
                end = mid;
            } else if (A[mid] < target) {
                start = mid;
            } else {
                return mid;
            }
        }

        if (A[start] >= target) {
            return start;
        } else if (A[end] >= target) {
            return end;
        } else {
            return end + 1;
        }
    }
}