[leetcode] Search in Rotated Sorted Array

Suppose a sorted array is rotated at some pivot unknown to you beforehand.

(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).

You are given a target value to search. If found in the array return its index, otherwise return -1.

You may assume no duplicate exists in the array.

题目大致的意思是有一个已经排好序的数组，现在把其中的元素按照某一个轴进行旋转，比如说0 1 2 4 5 6 7旋转之后变成了4 5 6 7 0 1 2现在给你一个数，让你输出其在数组中的索引，没找到的话输出-1。

class Solution {public:    int search(int A[], int n, int target) {// Start typing your C/C++ solution below// DO NOT write int main() functionint pivot=findP(A,n);int ret=binsearch(A,0,pivot,target);if(ret==-1)ret=binsearch(A,pivot+1,n-1,target);return ret;}int findP(int A[] , int n){int left=0; int right=n-1;int middle=0;if(A[left]<A[right])return 0;while(left<=right){middle=((right-left)>>1)+left;if(A[middle]>A[left])left=middle;else if(A[middle]<A[left])right=middle;elsereturn middle;}return middle;}int binsearch(int A[] , int left , int right , int target){while(left<=right){int middle=((right-left)>>1)+left;if(A[middle]<target)left=middle+1;else if(A[middle]>target)right=middle-1;elsereturn middle;}return -1;}};