Submission #563799

#	Time	Username	Problem	Language	Result	Execution time	Memory
563799		dantoh000	Mergers (JOI19_mergers)	C++14	0 / 100	123 ms	41252 KiB

mergers

#include <bits/stdc++.h>
using namespace std;
int n,k;
vector<int> G[1000005];
int c[1000005];
int low[1000005];
int num[1000005];
int p[1000005];
int sz[1000005];
int ct = 0;

int ans = 0;
int A[500005];
int B[500005];
void dfs(int u){
    num[u] = low[u] = ct++;
    sz[u] = 1;
    for (auto v : G[u]){
        if (num[v] == -1){
            p[v] = u;
            //printf("%d -> %d\n",u,v);
            dfs(v);
            if (low[v] > num[u] && u <= n && v <= n){
                //printf("%d %d\n",u,v);
                if (A[v] == 0){
                    A[v] = 1;
                }
            }
            low[u] = min(low[v], low[u]);
        }
        else if (v != p[u]){
            low[u] = min(num[v], low[u]);
        }
    }
}
void dfs2(int u, int p){
    for (auto v : G[u]){
        if (v == p) continue;
        if (v > n) continue;
        dfs2(v, u);
        B[u] |= B[v];
    }
    if (B[u] == 0 && A[u] == 1){
        ans++;
        B[u] = 1;
    }
}
int main(){
    scanf("%d%d",&n,&k);

    for (int i = 1; i < n; i++){
        int a,b;
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
    for (int i = 1; i <= n; i++){
        scanf("%d",&c[i]);
        G[i].push_back(n+c[i]);
        G[n+c[i]].push_back(i);
    }
    memset(low,-1,sizeof(low));
    memset(num,-1,sizeof(num));

    dfs(1);
    dfs2(1, -1);
    if (ans == 0) printf("0");
    else printf("%d",max(ans-1,1));
}

Compilation message (stderr)

mergers.cpp: In function 'int main()':
mergers.cpp:49:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |     scanf("%d%d",&n,&k);
      |     ~~~~~^~~~~~~~~~~~~~
mergers.cpp:53:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |         scanf("%d%d",&a,&b);
      |         ~~~~~^~~~~~~~~~~~~~
mergers.cpp:58:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |         scanf("%d",&c[i]);
      |         ~~~~~^~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30