P1464 Function

// Problem: P1464 Function
// Contest: Luogu
// URL: https://www.luogu.com.cn/problem/P1464
// Memory Limit: 125 MB
// Time Limit: 1000 ms
// User: Pannnn
 
#include <bits/stdc++.h>
 
using namespace std;
 
template<class T>
void printVector(const T &a) {
    cout << "[ ";
    for (size_t i = 0; i < a.size(); ++i) {
        cout << a[i] << (i == a.size() - 1 ? " " : ", ");
    }
    cout << "]" << endl;
}
 
template<class T>
using matrix2 = vector<vector<T>>;
 
template<class T>
vector<vector<T>> getMatrix2(size_t n, size_t m, T init = T()) {
    return vector<vector<T>>(n, vector<T>(m, init));
}
 
template<class T>
using matrix3 = vector<vector<vector<T>>>;
 
template<class T>
vector<vector<vector<T>>> getMatrix3(size_t x, size_t y, size_t z, T init = T()) {
    return vector<vector<vector<T>>>(x, vector<vector<T>>(y, vector<T>(z, init)));
}
 
long long getValue(long long a, long long b, long long c, matrix3<int> &info) {
    if (a <= 0 || b <= 0 || c <= 0) {
        return 1LL;
    }
    if (a > 20 || b > 20 || c > 20) {
        return getValue(20, 20, 20, info);
    }
    if (info[a][b][c] != 0) {
        return info[a][b][c];
    }
    if (a < b && b < c) {
        info[a][b][c] = getValue(a, b, c - 1, info) + getValue(a, b - 1, c - 1, info) 
            - getValue(a, b - 1, c, info);
    } else {
        info[a][b][c] = getValue(a - 1, b, c, info) + getValue(a - 1, b - 1, c, info)
            + getValue(a - 1, b, c - 1, info) - getValue(a - 1, b - 1, c - 1, info);
    }
    return info[a][b][c];
}
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    matrix3<int> info = getMatrix3<int>(21, 21, 21);
    long long x, y, z;
    while (cin >> x >> y >> z && (x != -1 || y != -1 || z != -1)) {
        long long res = getValue(x, y, z, info);
        printf("w(%lld, %lld, %lld) = %lld\n", x, y, z, res);
    }
    
    return 0;
}