[leetcode]Search in Rotated Sorted Array

简单题吧。用递归解决了。中间有个A[start] <= A[mid]的等号一开始没加。想来因为采用 / 2，mid可能会偏向start一方并mid==start的。

public class Solution {

    public int search(int[] A, int target) {

        // Start typing your Java solution below

        // DO NOT write main() function

        return search(A, target, 0, A.length - 1);

    }

    

    public int search(int[] A, int target, int start, int end) {

    	if (start > end) return -1;

    	int mid = (start + end) / 2;

    	if (A[mid] == target) return mid;

    	

    	if (A[start] <= A[mid]) { // left part sorted

    		if (target >= A[start] && target < A[mid]) {

    			return search(A, target, start, mid-1);

    		}

    		else if (target > A[mid] || target <= A[end]) {

    			return search(A, target, mid+1, end);

    		}

    	}

    	else // left left part unsorted

    	{

    		if (target >= A[start] || target < A[mid]) {

    			return search(A, target, start, mid-1);

    		}

    		else if (target > A[mid] && target <= A[end]) {

    			return search(A, target, mid+1, end);

    		}

    	}

    	return -1;

    }

}