Merge pull request rathoresrikant#551 from z3r0dmg/patch-5

Euler Totient function

Algorithms/Mathematical Algorithms/EulerTotient.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int phi(int n) {
+    int result = n;
+    for (int i = 2; i * i <= n; i++) {
+        if(n % i == 0) {
+            while(n % i == 0)
+                n /= i;
+            result -= result / i;
+        }
+    }
+    if(n > 1)
+        result -= result / n;
+    return result;
+}
+
+int main(){
+
+    int n;
+    cin>>n;
+    cout<<phi(n);
+    cout<<'\n';
+}