Search in Rotated Sorted Array

地址：https://oj.leetcode.com/problems/search-in-rotated-sorted-array/

非递归进行剪枝搜索版本号：

public class Solution {
	public int search(int[] A, int target) {
		int low =0, high = A.length-1;
			// high 小于target 从low開始搜索
			if(A[high]<target){
				int pivot = A[high];
				while(low<=high ){
					// 假设low大于target 或者low小于pivot 直接返回没找到
					if(A[low]>target || A[low]<pivot){
						return -1;
					}else {
						if(A[low]==target)
							return low;
					}
					low++;
				}
			}else {
				int pivot = A[high];
				while(low<=high){
					if(A[high]<target || A[high]>pivot){
						return -1;
					}
					if(A[high]==target)
						return high;
					high--;
				}
			}
		return -1;
	}
}

递归版本号实现：

public class Solution {
       public static int search(int[] A, int target) {  
        return rec(A, target, 0, A.length-1);  
    }  
       
    // 递归查找  
    public static int rec(int[] A, int target, int low, int high){  
        if(low > high){              // 没找到的情况  
            return -1;  
        }  
           
        int mid = low + (high-low)/2;  
        if(A[mid] == target){       // 找到了  
            return mid;  
        }  
           
        int res = rec(A, target, low, mid-1);       // 在左側查找  
        if(res == -1){          // 假设左側没找到。继续在右側查找  
            res = rec(A, target, mid+1, high);  
        }  
           
        return res;  
    }  
}