Submission #1268468

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268468		ducdev	Paths (BOI18_paths)	C++17	100 / 100	272 ms	52272 KiB

paths

// Author: 4uckd3v - Nguyen Cao Duc
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int MAX_N = 3e5;
const int MOD = 1e9 + 7;

int n, m, k;
int color[MAX_N + 5];
ll dp[1 << 5][MAX_N + 5];
vector<int> adj[MAX_N + 5];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (fopen("MAIN.INP", "r")) {
        freopen("MAIN.INP", "r", stdin);
        freopen("MAIN.OUT", "w", stdout);
    };

    cin >> n >> m >> k;
    for (int u = 1; u <= n; u++) {
        cin >> color[u];
        color[u]--;
    };

    while (m--) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    };

    ll res = 0;
    for (int u = 1; u <= n; u++) dp[1 << color[u]][u] = 1;

    for (int mask = 1; mask < (1 << k); mask++) {
        for (int u = 1; u <= n; u++) {
            for (int v : adj[u]) {
                if (mask >> color[v] & 1) continue;
                dp[mask ^ (1 << color[v])][v] += dp[mask][u];
            };
            if (__builtin_popcount(mask) > 1) res += dp[mask][u];
        };
    };

    cout << res;
};

Compilation message (stderr)

paths.cpp: In function 'int main()':
paths.cpp:19:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |         freopen("MAIN.INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
paths.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen("MAIN.OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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