Package g1901_2000.s1995_count_special_quadruplets

Class Solution

java.lang.Object

g1901_2000.s1995_count_special_quadruplets.Solution

public class Solution
extends Object

1995 - Count Special Quadruplets.<p>Easy</p> <p>Given a <strong>0-indexed</strong> integer array <code>nums</code>, return <em>the number of <strong>distinct</strong> quadruplets</em> <code>(a, b, c, d)</code> <em>such that:</em></p> <ul> <li><code>nums[a] + nums[b] + nums[c] == nums[d]</code>, and</li> <li><code>a < b < c < d</code></li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> nums = [1,2,3,6]</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> The only quadruplet that satisfies the requirement is (0, 1, 2, 3) because 1 + 2 + 3 == 6.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> nums = [3,3,6,4,5]</p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong> There are no such quadruplets in [3,3,6,4,5].</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> nums = [1,1,1,3,5]</p> <p><strong>Output:</strong> 4</p> <p><strong>Explanation:</strong> The 4 quadruplets that satisfy the requirement are:</p> <ul> <li> <p>(0, 1, 2, 3): 1 + 1 + 1 == 3</p> </li> <li> <p>(0, 1, 3, 4): 1 + 1 + 3 == 5</p> </li> <li> <p>(0, 2, 3, 4): 1 + 1 + 3 == 5</p> </li> <li> <p>(1, 2, 3, 4): 1 + 1 + 3 == 5</p> </li> </ul> <p><strong>Constraints:</strong></p> <ul> <li><code>4 <= nums.length <= 50</code></li> <li><code>1 <= nums[i] <= 100</code></li> </ul>

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)