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).
Find the minimum element.
You may assume no duplicate exists in the array.

我們來觀察一下：
01234
12340
23401
34012
40123
如果中間的值大于左邊和右邊的，那我們要找的在右邊
如果中間值小于左邊的和右邊的，那我們要找的在左邊
如果中間值大于左邊小于右邊的，那左邊的就是我們要找的

var findMin = function(nums) {
    var left = 0;
    var right = nums.length - 1;
    while (left<right) {
        var mid = left + parseInt((right - left) / 2);
        if (nums[mid]>=nums[left]&&nums[mid]>=nums[right]) 
            left = mid + 1;
        else if (nums[mid]<=nums[left]&&nums[mid]<=nums[right]) 
            right = mid;
        else if (nums[mid]>=nums[left]&&nums[mid]<=nums[right]) 
            return nums[left];
    }
    return nums[left];
};