Submission #645474

#	Time	Username	Problem	Language	Result	Execution time	Memory
645474		mychecksedad	Paths (BOI18_paths)	C++17	43 / 100	376 ms	49956 KiB

paths

/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;



int n, m, k, a[N];
ll ans = 0, dp[N][3];
vector<int> g[N];
vector<bool> vis(N);
void dfs(int v, int p){
    vis[v] = 1;
    for(int u: g[v]){
        int mask = (1<<a[v]) + (1<<a[u]);
        if(a[v] != a[u]){
            ans++;
            if(mask == 3) ans += dp[u][2];
            if(mask == 5) ans += dp[u][1];
            if(mask == 6) ans += dp[u][0];
        }
        if(vis[u]) continue;
        dfs(u, v);
    }
}


void dfs1(int v, int p, int d, vector<int> &x){
    if(d>1){    
        ans++;
    }
    for(int u: g[v]){
        if(u != p){
            if(x[a[u]]) continue;
            x[a[u]] = 1;
            dfs1(u, v, d + 1, x);
            x[a[u]] = 0;
        }
    }
}

void solve(){
    cin >> n >> m >> k;
    for(int i = 1; i <= n; ++i) cin >> a[i];
    for(int i = 1; i <= n; ++i) --a[i], dp[i][0] = dp[i][1] = dp[i][2] = 0;
    for(int i = 0; i < m; ++i){
        int u, v; cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
        dp[u][a[v]]++;
        dp[v][a[u]]++;
    }
    if(n <= 100){
        vector<int> v (4);
        for(int i = 1; i <= n; ++i){
            v[0] = v[1] = v[2] = v[3] = 0;
            v[a[i]] = 1; 
            dfs1(i, 0, 1, v);
        }
    }else{
        for(int i = 1; i <= n; ++i) if(!vis[i]) dfs(i, 0);
    }


    cout << ans;
}   





int main(){
    cin.tie(0); ios::sync_with_stdio(0);
    int T = 1, aa;
    // cin >> T;aa=T;
    while(T--){
        // cout << "Case #" << aa-T << ": ";
        solve();
        cout << '\n';
    }
    return 0;
 
}

Compilation message (stderr)

paths.cpp: In function 'int main()':
paths.cpp:83:16: warning: unused variable 'aa' [-Wunused-variable]
   83 |     int T = 1, aa;
      |                ^~

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