Package g1901_2000.s1995_count_special_quadruplets

Class Solution

java.lang.Object
g1901_2000.s1995_count_special_quadruplets.Solution
public class Solution extends java.lang.Object
1995 - Count Special Quadruplets.

Easy

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

Example 1:

Input: nums = [1,2,3,6]

Output: 1

Explanation: The only quadruplet that satisfies the requirement is (0, 1, 2, 3) because 1 + 2 + 3 == 6.

Example 2:

Input: nums = [3,3,6,4,5]

Output: 0

Explanation: There are no such quadruplets in [3,3,6,4,5].

Example 3:

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

Constraints:

  • 4 <= nums.length <= 50
  • 1 <= nums[i] <= 100

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    countQuadruplets(int[] nums)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • countQuadruplets

      public int countQuadruplets(int[] nums)