Update binary-exp.md

UtkarshSingh1923 · web-flow · commit 1e8df9f2bade · 2025-07-01T23:17:18.000+05:30
Distributive law of modulo over multiplication to handle overflow
diff --git a/src/algebra/binary-exp.md b/src/algebra/binary-exp.md
@@ -104,8 +104,8 @@ long long binpow(long long a, long long b, long long m) {
     long long res = 1;
     while (b > 0) {
         if (b & 1)
-            res = res * a % m;
-        a = a * a % m;
+            res = (res%m * a%m) % m;
+        a = (a%m * a%m) % m;
         b >>= 1;
     }
     return res;
