[LintCode] #159 Find Minimum in Rotated Sorted Array

1) [mid] > [start] move right, else move left
2) edge case: the array is sorted

public class Solution {
    /**
     * @param num: a rotated sorted array
     * @return: the minimum number in the array
     */
    public int findMin(int[] nums) {
        // write your code here
        if (nums == null || nums.length == 0) {
            return -1;
        }
        if (nums[0] < nums[nums.length - 1]) { //T_T!!!!!
            return nums[0];
        }
        int start = 0;
        int end = nums.length - 1;
        while (start + 1 < end) {
            int mid = start + (end - start) / 2;
            if (nums[0] < nums[mid]) {
                start = mid;
            } else {
                end = mid;
            }
        }
        
        if (nums[start] < nums[end]) {
            return nums[start];
        } else {
            return nums[end];
        }
    }
}