[leetcode]Find Minimum in Rotated Sorted Array

二分

class Solution {

public:

    /*

    test: [1]

    test: [2, 1]

    test: [3, 1, 2]

    test: [2, 3, 1]

    test: [3, 4, 1, 2]

    test: [3, 4, 5, 1, 2]

    */

    int findMin(vector<int> &num) {

        int size = num.size();

        int min = num[size-1];

        int left = 0;

        int right = size - 1;

        while (left <= right) {

            int mid = (left + right) / 2;

            if (((mid - 1 >= 0 && num[mid] < num[mid-1]) || (mid == 0)) &&

                ((mid + 1 < size && num[mid] < num[mid+1]) || (mid == size - 1))) {

                return num[mid];

            }

            if (num[mid] > min) { 

                left = mid + 1;

            } else {

                right = mid - 1;

                min = num[mid];

            }        

        }

    }

};