Search-insert-position

题目描述

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

public class Solution {
    public int searchInsert(int[] A, int target) {
        int i = 0;
        for(i = 0 ; i < A.length ; i++)
        {
            if(target == A[i])
                 return i;
            else if(target < A[i])
                return i;
        }
        return A.length;
    }
}

or:

public class Solution {
    public int searchInsert(int[] A, int target) {
        int head = 0;
        int tail = A.length - 1;
        while(head <= tail)
        {
            int mid = (head + tail) / 2;
            if(A[mid] == target)
                return mid;
            else if(A[mid] > target)
                tail = mid - 1;
            else 
                head = mid + 1;;
        }
        return head;
    }
}

directly search or use the binary search