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829. Consecutive Numbers Sum

  • Time: $O(n)$
  • Space: $O(1)$
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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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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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class Solution:
  def consecutiveNumbersSum(self, n: int) -> int:
    ans = 0
    i = 1
    triangleNum = 1
    while triangleNum <= n:
      if (n - triangleNum) % i == 0:
        ans += 1
      i += 1
      triangleNum += i
    return ans