DDSA Solutions

829. Consecutive Numbers Sum

HardView on LeetCode
Math
Time: O(√n)
Space: O(1)

Problem Overview

Consecutive Numbers Sum (Hard) asks you to solve a structured algorithmic task. This is a common Math pattern in coding interviews. For each k, check if (n - k(k-1)/2) is positive and divisible by k; count valid partitions.

A full step-by-step explanation is being added. See the study guide for pattern-based practice.

Approach

For each k, check if (n - k(k-1)/2) is positive and divisible by k; count valid partitions.

Related patterns: Math

829.cs
C#
// Approach: For each k, check if (n - k(k-1)/2) is positive and divisible by k; count valid partitions.
// Time: O(√n) Space: O(1)

public class Solution
{
    public int ConsecutiveNumbersSum(int n)
    {
        int ans = 0;
        for (int i = 1, triangleNum = i; triangleNum <= n; ++i, triangleNum += i)
            if ((n - triangleNum) % i == 0)
                ++ans;
        return ans;
    }
}
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