Submission #14705

#	Time	Username	Problem	Language	Result	Execution time	Memory
14705		gs14004	우호 조약 체결 (JOI14_friends)	C++14	Compilation error	0 ms	0 KiB

friends

#include <cstdio>
#include <vector>
#include <queue>
using namespace std;

struct disj{
    int pa[100005], sz[100005];
    void init(int n){
        for(int i=1; i<=n; i++) pa[i] = i, sz[i] = 1;
    }
    int find(int x){
        if(pa[x] == x) return x;
        return pa[x] = find(pa[x]);
    }
    int size(int x){
        return sz[find(x)];
    }
    int uni(int p, int q){
        p = find(p);
        q = find(q);
        if(p == q) return 0;
        pa[q] = p;
        sz[p] += sz[q];
        return 1;
    }
}disj;

bool vis[100005];
int n,m;
vector<int> g[100005], ng[100005];
queue<int> q;

int main(){
    scanf("%d %d",&n,&m);
    disj.init(n);
    for (int i=0; i<m; i++) {
        int x,y;
        scanf("%d %d",&x,&y);
        g[x].push_back(y);
    }
    for (int i=1; i<=n; i++) {
        for (int j=0; j+1<g[i].size(); j++) {
            disj.uni(g[i][j],g[i][j+1]);
        }
    }
    for (int i=1; i<=n; i++) {
        if(disj.size(i) != 1){
            q.push(i);
            vis[i] = 1;
        }
    }
    while (!q.empty()) {
        int qf = q.front();
        q.pop();
        if(!g[qf].empty() && disj.size(g[qf][0]) != 1 && !vis[g[qf][0]]){
            disj.uni(g[qf][0],qf);
            vis[g[qf][0]] = 1;
            q.push(g[qf][0]);
        }
    }
    long long ret = 0;
    memset(vis,0,sizeof(vis));
    for (int i=1; i<=n; i++) {
        if(!vis[disj.find(i)]){
            vis[disj.find(i)] = 1;
            ret += 1ll * disj.size(i) * (disj.size(i) - 1);
        }
    }
    for (int i=1; i<=n; i++) {
        for (int &j : g[i]){
            if(disj.find(i) != disj.find(j)) ret++;
        }
    }
    printf("%lld",ret);
}

Compilation message (stderr)

friends.cpp: In function ‘int main()’:
friends.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j=0; j+1<g[i].size(); j++) {
                          ^
friends.cpp:62:29: error: ‘memset’ was not declared in this scope
     memset(vis,0,sizeof(vis));
                             ^
friends.cpp:34:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&m);
                         ^
friends.cpp:38:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&x,&y);
                             ^