leetcode 1995. 统计特殊四元组

java:

就最简单的方法 时间复杂度很高  每日一题罢了

class Solution {
    public int countQuadruplets(int[] nums) {
        int count = 0;
        int n = nums.length;
        for(int a = 0; a < n; ++a){
            for(int b = a + 1; b < n; ++b){
                for(int c= b + 1; c < n; ++c){
                    for(int d = c + 1; d < n; ++d){
                        if(nums[a] + nums[b] + nums[c] == nums[d]){
                            ++count;
                        }
                    }
                }
            }
        }
        return count;
    }
}

python3:

class Solution:
    def countQuadruplets(self, nums: List[int]) -> int:
        n = len(nums)
        count = 0
        for a in range(0, n):
            for b in range(a + 1, n):
                for c in range(b + 1, n):
                    for d in range(c + 1, n):
                        if nums[a] + nums[b] + nums[c] == nums[d]:
                            count += 1
        return count