Submission #1034643

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034643		anango	Paths (BOI18_paths)	C++17	100 / 100	387 ms	62292 KiB

paths

#include <bits/stdc++.h>
#define int long long
using namespace std;
int INF = 1LL<<30;

signed main() {
    #ifdef ONLINE_JUDGE
    	ios_base::sync_with_stdio(false);
    	cin.tie(NULL);
    #endif //fast IO
    int n,m,k; cin >> n >> m >> k;
    vector<vector<int>> adjlist(n);
    vector<int> col(n); for (int i=0; i<n; i++) {cin >> col[i]; col[i]--;}
    for (int i=0; i<m; i++) {
        int u,v; cin >> u >> v; u--; v--;
        adjlist[u].push_back(v); adjlist[v].push_back(u);
    }
    int dp[n][1<<k];
    for (int i=0; i<n; i++) {
        for (int j=0; j<1<<k; j++) {
            dp[i][j] = 0;
        }
    }
    //dp[i][j] = number of paths with  this bitmask of colours used, ending in this vertex
    for (int i=0; i<n; i++) {
        dp[i][1<<col[i]]++;
    }
    for (int mask=1; mask<1<<k; mask++) {
        for (int i=0; i<n; i++) {
            if (mask&(1<<col[i])==0) continue;
            for (int j:adjlist[i]) {
                dp[i][mask]+=dp[j][mask^(1<<col[i])];
            }
        }
    }
    int su=0;
    for (int i=0; i<n; i++) {
        for (int j=0; j<1<<k; j++) {
            su+=dp[i][j];
        }
    }
    cout << su-n << endl;
    
}

Compilation message (stderr)

paths.cpp: In function 'int main()':
paths.cpp:30:33: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   30 |             if (mask&(1<<col[i])==0) continue;
      |                      ~~~~~~~~~~~^~~

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