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.

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 (n == 0) return -1;

int l = 0;
int u = n-1;
while(l <= u)
{
int mid = l+(u-l)/2;

if (A[mid] == target)
return mid;
else if (A[mid] > A[u])
{
if (A[l] <= target && target < A[mid])
{
u = mid - 1;
}
else
{
l = mid + 1;
}
}
else
{
if (A[u] >= target && target > A[mid])
{
l = mid + 1;
}
else
{
u = mid - 1;
}
}
}
return -1;
}
};