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Find Minimum 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).

Find the minimum element.

You may assume no duplicate exists in the array.

分析:Seearch in rotated sorted array的变种,关键在于确定binary search的左右边界。代码如下:

class Solution {public:    int findMin(vector<int> &num) {        int n = num.size();                if(n == 1) return num[0];        if(n == 2) return min(num[0], num[1]);        if(num[0] < num[n-1])            return num[0];                int l = 0, r = n-1;                while(l <= r){            int mid = (l + r)/2;            if(mid == n-1 && num[mid] < num[mid-1] || num[mid] < num[mid-1] && num[mid] < num[mid+1])                return num[mid];            if(num[mid] >= num[0])                l = mid + 1;            else r = mid - 1;        }    }};

 

Find Minimum in Rotated Sorted Array