insert divsum

1 files changed, 7 insertions, 8 deletions

diff --git a/content/math/divSum.cpp b/content/math/divSum.cpp
index dc4bc4d..48302b5 100644
--- a/content/math/divSum.cpp
+++ b/content/math/divSum.cpp
@@ -1,9 +1,8 @@
-// Calculates the sum of (a*i+b)/m for i=0..(n-1) in O(log(n))
-// Note that b should not be negative!
 ll divSum(ll n, ll m, ll a, ll b){
-	if(m == 0) return 0;
-	ll ans = a/m * n*(n-1) / 2 + b/m * n;
-	a %= m, b %= m;
-	ll y = (a*(n-1)+b)/m;
-	return ans + y*(n-1) - divSum(y, a, m, m-b-1);
-}
\ No newline at end of file
+	if (m == 0) return 0;
+	ll ans = a/m * n*(n-1)/2 + b/m * n;
+	a %= m;
+	b %= m;
+	ll y = (a*(n-1)+b) / m;
+	return ans + y * (n-1) - divSum(y, a, m, m-b-1);
+}