Search in Rotated Sorted Array

Posted 2023-01-20 IIcyZhao

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.

class Solution 
public:
    int search(int A[], int n, int target) 
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (A[0] == target) 
            return 0;
         else if (A[0] > target) 
            if (A[n-1] == target) 
                return n-1;
            
            for (int i = n-2; i > 0 && A[i] < A[i+1]; --i) 
                if (A[i] == target) 
                    return i;
                
            
         else 
            for (int i = 1; i < n && A[i-1] < A[i]; ++i) 
                if (A[i] == target) 
                    return i;
                
            
        
        return -1;
    
;