제출 #563872

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
563872		dantoh000	Mergers (JOI19_mergers)	C++14	100 / 100	943 ms	96660 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 ct = 0;

int pa[500005];
int eg[500005];
int rk[500005];
void init(int n){
    for (int i = 1; i <= n; i++){
        pa[i] = i; rk[i] = 0;
        eg[i] = 0;
    }
}
int fin(int x){
    return pa[x] == x ? x : pa[x] = fin(pa[x]);
}
void un(int x, int y){
    x = fin(x), y = fin(y);
    if (x == y) return;
    if (rk[x] < rk[y]) swap(x,y);
    pa[y] = x;
    eg[x] += eg[y];
    if (rk[x] == rk[y]) rk[x]++;
}

void dfs2(int u){
    for (auto v : G[u]){
        if (v <= n){
            if (v == p[u]) continue;
            p[v] = u;
            dfs2(v);
            if (low[v] <= num[u]){
                un(u,v);
            }
            else{
                //printf("bridge %d %d\n",u,v);
                eg[fin(u)]++;
                eg[fin(v)]++;
            }

        }
    }
}

void dfs(int u, int P){
    num[u] = low[u] = ct++;
    for (auto v : G[u]){
        if (num[v] == -1){
            //printf("%d -> %d\n",u,v);
            dfs(v, u);
            low[u] = min(low[v], low[u]);
        }
        else if (v != P){
            low[u] = min(num[v], low[u]);
        }
    }
}

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));
    init(n);
    dfs(1,-1);
    p[1] = 0;
    dfs2(1);

    int ans = 0;
    for (int i = 1; i <= n; i++){
        if (i == pa[i] && eg[i] == 1) {
            //printf("%d ",i);
            ans++;
        }
    }
    printf("%d",(ans+1)/2);
}

컴파일 시 표준 에러 (stderr) 메시지

mergers.cpp: In function 'int main()':
mergers.cpp:66:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |     scanf("%d%d",&n,&k);
      |     ~~~~~^~~~~~~~~~~~~~
mergers.cpp:70:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         scanf("%d%d",&a,&b);
      |         ~~~~~^~~~~~~~~~~~~~
mergers.cpp:75:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         scanf("%d",&c[i]);
      |         ~~~~~^~~~~~~~~~~~

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