분할 정복 알고리즘 - (x * y) % m

Divide_And_Conquer_Add.cpp

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;

ll f (ll x, ll y, ll m) {
    if (y == 0) return 0;
    if (y == 1) return x % m;
    if (y % 2 == 1) {
        ll sib = f (x, y - 1, m) % m;
        return ((sib % m) + x % m) % m;
    }
    else {
        ll al = f (x, y / 2, m) % m;
        return ((al % m) + (al % m)) % m;
    }
}

int main () {
    ll s, ib, al;
    cin >> s >> ib >> al;
    cout << f (s, ib ,al);
    return 0;
}