4 ms·
Not sure why you're mentioning this as it's in the SO question: "The correct answer can be calculated using 1 + 2 + ... + n = n(n+1)/2"
by cgh 13y ago
Not sure why you're mentioning this as it's in the SO question:
"The correct answer can be calculated using
1 + 2 + ... + n = n(n+1)/2"