Submission #1090277

#	Time	Username	Problem	Language	Result	Execution time	Memory
1090277		Gourougourou	Untitled (POI11_kon)	C++17	100 / 100	1190 ms	117128 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 5001;
const int MOD = 1e4+7;
int deg[MAXN], cnt[MAXN], fact[MAXN];

int fastPow(int a, int b) {
    if (b == 0) return 1;
    if (b & 1) return (a * fastPow(a, b-1)) % MOD;
    return fastPow((a*a)%MOD, b/2);
}
int rev(int a) {
    return fastPow(a, MOD-2);
}
int choose(int a, int b) {
    return (((fact[a]*rev(fact[a-b])) % MOD) * rev(fact[b])) % MOD;
}
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    fact[0] = 1;
    for (int i = 1; i<MAXN; ++i) fact[i] = (i*fact[i-1]) % MOD;
    int n, m = 0; cin >> n;
    for (int i = 0; i<n; ++i) {
        int sz,a; cin >> sz;
        deg[i] = sz; ++cnt[sz];
        m += sz;
        while (sz--) {
            cin >> a;
        }
    }
    m /= 2;
    sort(deg,deg+n);
    int same = 1, degSum = 0, x = 1, ans = 0;
    for (int i = n-1; i; --i, ++x) {
        if (i != n-1) {
            if (deg[i] == deg[i+1]) ++same;
            else same = 1;
        }
        degSum += deg[i];
        if (degSum - (x*(x-1))/2 == m) {
            ans += choose(cnt[deg[i]], same);
        }
    }
    cout << ans;
}

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