Submission #1183973

#	Time	Username	Problem	Language	Result	Execution time	Memory
1183973		alterio	Paths (BOI18_paths)	C++20	70 / 100	172 ms	92776 KiB

paths

#include <bits/stdc++.h>

using namespace std;

#define endl '\n'
#define ll long long
#define all(x) (x).begin(), (x).end()

const int mxn = 3e5 + 10, mxk = 5;

vector<int> g[mxn], val(mxn), masks[5];

ll dp[mxn][1 << mxk];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m, k;
    cin >> n >> m >> k;
    for (int i = 1; i <= n; i++) cin >> val[i], val[i]--;
    for (int i = 0; i < m; i++) {
        int f, t;
        cin >> f >> t;
        g[f].push_back(t);
        g[t].push_back(f);
    }
    for (int i = 1; i < (1 << k); i++) masks[__builtin_popcount(i)].push_back(i);
    for (int i = 1; i <= n; i++) dp[i][1 << val[i]] = 1;
    for (int i = 1; i < k; i++) {
        for (int j = 1; j <= n; j++) {
            for (auto mask : masks[i]) {
                if (!dp[j][mask]) continue;
                for (auto to : g[j]) {
                    if (!((1 << val[to]) & mask)) {
                        int newMask = mask | (1 << val[to]);
                        dp[to][newMask] += dp[j][mask];
                    }
                }
            }
        }
    }
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 2; j <= k; j++) {
            for (auto mask : masks[j]) {
                ans += dp[i][mask];
            }
        }
    }
    cout << ans;
}

• Subtask 1: 23 / 23
• Subtask 2: 20 / 20
• Subtask 3: 27 / 27
• Subtask 4: 0 / 30