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Sum N Numbers

Easy
Python
def sum_n(n):
    return n*(n+1)//2
Java
public int sumN(int n){
    return n*(n+1)/2;
}

Key Insight

Gauss formula. Nearly identical. // vs /.

Python → Java Differences

  • // vs /
  • One-liner both
  • Gauss formula
Python
def sum_n(n):
    return n*(n+1)//2
Java
public int sumN(int n){
    return n*(n+1)/2;
}

Algorithm Steps

1. Return n*(n+1)/2
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