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.

连着三个题都好简单，差不多的思路，lucky……

#include<stdio.h>

int search(int A[], int n, int target) {
    int i,j,tmp;
    for(i=0;i<n-1;i++){
        if((A[i])>A[i+1]) break;
    }
    tmp=i;
    if(target>=A[0]){
        i=0;
        j=tmp;
    }
    else {
        i=tmp+1;
        j=n-1;
    }
    while(i<=j){
        if(A[(i+j)/2]==target) return (i+j)/2;
        if(A[(i+j)/2]>target) j--;
        else i++;
    }
    return -1;
}

Search in Rotated Sorted Array