描述
Given a 0-indexed integer array nums, return the number of distinct quadruplets (a, b, c, d) such that:
- nums[a] + nums[b] + nums[c] == nums[d], and
- a < b < c < d
测试用例
Input: nums = [1,1,1,3,5]
Output: 4
Explanation: The 4 quadruplets that satisfy the requirement are:
- (0, 1, 2, 3): 1 + 1 + 1 == 3
- (0, 1, 3, 4): 1 + 1 + 3 == 5
- (0, 2, 3, 4): 1 + 1 + 3 == 5
- (1, 2, 3, 4): 1 + 1 + 3 == 5题解
var countQuadruplets = function (nums) {
if (nums.length < 4) return 0;
let sum = 0,
len = nums.length;
// 后面至少保留3位
for (let i = 0; i < len - 3; i++) {
for (let j = i + 1; j < len - 2; j++) {
for (let k = j + 1; k < len - 1; k++) {
let _sum = nums[i] + nums[j] + nums[k];
let r = len - 1;
while (k < r) {
if (_sum === nums[r]) {
sum++;
}
r--;
}
}
}
}
return sum;
};结果
Accepted
211/211 cases passed (436 ms)
Your runtime beats 5.19 % of javascript submissions
Your memory usage beats 5.19 % of javascript submissions (46.4 MB)
