[Templates That Are Usually Used]Greatest Common Divisor

#include <iostream>#include <cstdio>#include <algorithm>using namespace std;int gcd(int a, int b){    int ans;    if(a < b)        swap(a, b);    if(b == 0) ans = a;    else        ans = gcd(b, a%b);    return ans;}int main(){    int a, b, c;    cin >> a >> b;    c = gcd(a, b);    cout << c << endl;    return 0;}

//优化：

int gcd(int x, int y){    return y == 0 ? x : gcd(y, x%y);}