LeetCode

题目：

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

思路：

二分查找

package array;

public class SearchInsertPosition {

    public int searchInsert(int[] nums, int target) {
        int n;
        if (nums == null || (n = nums.length) == 0) return 0;

        int start = 0;
        int end = n - 1;
        int index = -1;

        while (start <= end) {
            int mid = (end - start) / 2 + start;
            if (nums[mid] == target) {
                index = mid;
                break;
            } else if (nums[mid] < target) {
                start = mid + 1;
            } else {
                end = mid - 1;
            }
        }
        
        if (index == -1)
            index = end + 1;
        
        return index;
    }
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        SearchInsertPosition s = new SearchInsertPosition();
        int[] nums = { 1, 3, 5 };
        System.out.println(s.searchInsert(nums, 7));
    }

}