Submission #1207968

#	Time	Username	Problem	Language	Result	Execution time	Memory
1207968		segfault_ikuyo	Race (IOI11_race)	C++20	Compilation error	0 ms	0 KiB

race

#include <bits/stdc++.h>

using namespace std;
#define int long long
#define pb push_back
#define pii pair<int,int>

const int maxn=2*1e5+5;
const int maxk=1e6+5;

vector<pii> adj[maxn];
pii path[maxk];
int vis[maxn], siz[maxn];
int n,k,a,b,c;
int ans;
queue<pii> q;

int dfssiz(int x, int pre){
    int sizz=1;
    for(pii i:adj[x]){
        if(i.first==pre||vis[i.first]) continue;
        sizz+=dfssiz(i.first,x);
    }
    siz[x]=sizz;
    //cout << x << '-' << siz[x] << '\n';
    return sizz;
}

int dfsget(int x, int pre, int c){
    for(pii i:adj[x]){
        if(i.first==pre||vis[i.first]) continue;
        if(siz[i.first]>=siz[c]/2) {
            return dfsget(i.first,x,c);
        }
    }
    return x;
}

void dfssolve(int x, int pre, int d, int dd, int c){
    if(dd>k) return;
    if(dd==k){
        ans=min(ans,d);
        return;
    }
    if(path[k-dd].second==c){
        ans=min(ans,path[k-dd].first+d);
    }
    for(pii i:adj[x]){
        if(i.first==pre||vis[i.first]) continue;
        dfssolve(i.first,x,d+1,dd+i.second,c);
    }
    
    q.push({d,dd});
   
}

int getcentroid(int x){
    dfssiz(x,-1);
    return dfsget(x,-1,x);
}

void solve(int x){
    if(vis[x]) return;
    int c=getcentroid(x);

    path[0]={0,c};
    pii cur;
    for(pii i:adj[c]){
        if(vis[i.first]) continue;
        //q.clear();
        dfssolve(i.first,c,1,i.second,c);
        while(!q.empty()){
            cur=q.front();
            q.pop();
            if(path[cur.second].second!=c) path[cur.second]={cur.first,c};
            else path[cur.second].first=min(cur.first,path[cur.second].first);
        }
        
    }

    vis[c]=1;
    for(pii i:adj[c]){
        if(vis[i.first]) continue;
        solve(i.first);
    }
}

signed main(){
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    memset(path,0xff,sizeof(path));
    cin >> n >> k;
    ans=LLONG_MAX;
    for(int i=0;i<n-1;i++){
        cin >> a >> b >> c;
        adj[a].pb({b,c});
        adj[b].pb({a,c});
    }
    solve(0);
    if(ans==LLONG_MAX) ans=-1;
    cout << ans << '\n';

    return 0;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/ccNuZNA4.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/cc0TPvmP.o:race.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/ccNuZNA4.o: in function `main':
grader.cpp:(.text.startup+0x28): undefined reference to `best_path(int, int, int (*) [2], int*)'
collect2: error: ld returned 1 exit status