b^p mod m

BidhanRoy · BidhanRoy · commit b354aabc5774 · 2014-06-01T11:38:40.000+06:00
diff --git a/Mathematics/Big Modular Exponentiation.cpp b/Mathematics/Big Modular Exponentiation.cpp
@@ -0,0 +1,14 @@
+long long powmod(long long b,long long p,long long m=0 ){
+	// b ^ p mod m
+	// 2 parameter means no mod
+    long long res = 1;
+    for( long long i=(1LL<<62); i; i>>=1){
+        res*=res; 
+        if(m>0) res%= m;
+        if(p&i) { 
+			res*=b; 
+			if(m>0) res%=m; 
+		}
+    }
+    return res;
+}
