Submission #1116075

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116075		vjudge1	Calvinball championship (CEOI15_teams)	C++17	10 / 100	6 ms	504 KiB

teams

#include <bits/stdc++.h>

using i64 = long long;

#ifdef DEBUG 
    #include "/home/ahmetalp/Desktop/Workplace/debug.h"
#else
    #define debug(...) void(23)
#endif

template<typename T>
T power(T a, i64 b) {
    T res = 1;
    while(b) {
        if(b & 1) {
            res *= a;
        }
        a *= a;
        b >>= 1;
    }
    return res;
}
 
constexpr int md = int(1E9) + 7;
struct MInt {
    int val;
    MInt() : val(0) {}
    template<typename T>
    MInt(T v) {
        if(-md <= v && v < md) {
            val = v;
        } else {
            val = v % md;
        }
        if(val < 0) {
            val += md;
        }
    }
    int operator() () { return val; }
    MInt operator+= (MInt rhs) {
        if((val += rhs.val) >= md) {
            val -= md;
        }
        return *this;
    }
    MInt operator-= (MInt rhs) {
        if((val -= rhs.val) < 0) {
            val += md;
        }
        return *this;
    }
    MInt operator*= (MInt rhs) {
        val = (int)(1LL * val * rhs.val % md);
        return *this;
    }
    MInt inv() {
        return power(*this, md - 2);
    }
    MInt operator/= (MInt rhs) {
        return *this *= rhs.inv();
    }
    bool operator== (MInt rhs) {
        return val == rhs.val;
    }
    bool operator!= (MInt rhs) {
        return val != rhs.val;
    }
};
MInt operator+ (MInt lhs, MInt rhs) {
    return lhs += rhs;
}
MInt operator- (MInt lhs, MInt rhs) {
    return lhs -= rhs;
}
MInt operator* (MInt lhs, MInt rhs) {
    return lhs *= rhs;
}
MInt operator/ (MInt lhs, MInt rhs) {
    return lhs /= rhs;
}
std::ostream& operator<< (std::ostream& os, MInt v) {
    return os << v();
}
std::string to_string(MInt x) {
    return to_string(x());
}
 
using Z = MInt;

constexpr int max_N = 100 + 5;

int N;
int A[max_N];
int mxc[max_N], usedc[max_N], visc[max_N];

struct Comb {
    int n;
    std::vector<Z> _fac, _inv_fac, _inv;
    Comb() : n{0}, _fac{1}, _inv_fac{1}, _inv{0} {}
    Comb(int _n) : Comb() {
        init(_n);
    }

    void init(int m) {
        _fac.resize(m + 1);
        _inv_fac.resize(m + 1);
        _inv.resize(m + 1);

        for(int i = n + 1; i <= m; ++i) {
            _fac[i] = _fac[i - 1] * i;
        }
        _inv_fac[m] = _fac[m].inv();
        for(int i = m; i > n; --i) {
            _inv_fac[i - 1] = _inv_fac[i] * i;
            _inv[i] = _inv_fac[i] * _fac[i - 1];
        }
        n = m;
    }

    Z fac(int m) {
        if(m > n) init(2 * m);
        return _fac[m];
    }
    Z inv_fac(int m) {
        if(m > n) init(2 * m);
        return _inv_fac[m];
    }
    Z inv(int m) {
        if(m > n) init(2 * m);
        return _inv[m];
    }
    Z binom(int m, int r) {
        if(m < r || r < 0) return 0;
        return fac(m) * inv_fac(m - r) * inv_fac(r);
    }
} comb;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    std::cin >> N;
    for (int i = 1; i <= N; ++i) {
        std::cin >> A[i];
    }

    Z ans = 1;
    for (int i = 1; i <= N; ++i) {
        for (int j = 1; j < A[i]; ++j) {
            int gap = N - i;
            int had = usedc[i - 1] + !visc[j];
            for (int k = std::max(mxc[i - 1], j); k <= N; ++k) {
                int need = k - had;
                if (need <= gap) {
                    ans += comb.binom(gap, need) * power(Z(k), gap - need);
                }
            }
        }

        mxc[i] = std::max(mxc[i - 1], A[i]);
        usedc[i] = usedc[i - 1] + !visc[A[i]];
        visc[A[i]] = true;
    }

    bool good = true;
    for (int i = 1; i <= mxc[i]; ++i) {
        good &= visc[i];
    }

    if (good) {
        std::cout << ans << '\n';
    } else {
        std::cout << "0\n";
    }

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10