153. Find Minimum in Rotated Sorted Array

發表於 | 分類於

problem

各元素唯一

solution

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class Solution {
public:
    int findMin(vector<int>& nums) {
        int n = nums.size();
        int l = 0, r = n-1;
        while(l<r){
            int mid = l + (r-l)/2;
            // 代表最小值會在 [mid+1, r] 之間
            if(nums[mid] > nums[r]) l = mid+1;
            // 右半部遞增，下次搜尋區間 [l, mid]
            else if(nums[mid] < nums[r]) r = mid;
        }
        return nums[l];
        
    }
};

analysis

  • time complexity O(logn)
  • space complexity O(1)