Submission #716044

#	Time	Username	Problem	Language	Result	Execution time	Memory
716044		Charizard2021	Paths (BOI18_paths)	C++17	100 / 100	594 ms	26700 KiB

paths

#include <bits/stdc++.h>

using namespace std;
int main() {
    int n, m, k;
    cin >> n >> m >> k;
    int colors[n];
    for(int i = 0; i < n; i++){
        cin >> colors[i];
        colors[i]--;
    }
    vector<int> adj[n];
    for(int i = 0; i < m; i++){
        int a, b;
        cin >> a >> b;
        a--;
        b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
	vector<int> order(k);
    for(int i = 0; i < k; i++){
        order[i] = i;
    }
	long long res = 0;
	vector<long long> dp(n);
    vector<long long> next(n);
	do {
        for(int i = 0; i < n; i++){
            if(colors[i] == order[0]){
                dp[i] = 1;
            }
            else{
                dp[i] = 0;
            }
        }
        for(int i = 1; i < k; i++){
            for(int j = 0; j < n; j++){
                long long x = 0;
                if(colors[j] == order[i]){
                    for(int y : adj[j]){
                        x += dp[y];
                    }
                }
                next[j] = x;
            }
            swap(dp, next);
            if(is_sorted(order.begin() + i + 1, order.end())){
                for(int j = 0; j < n; j++){
                    res += dp[j];
                }
            }
        }
	} while (next_permutation(order.begin(), order.end()));
	cout << res << "\n";
}

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