Submission #1020605

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020605		vjudge1	Flood (IOI07_flood)	C++17	100 / 100	171 ms	32008 KiB

flood

#include<bits/stdc++.h>
using namespace std;
int X[100100],Y[100100],lev[400100],side[100100][4][2],Xof[400100];
bitset<400100>vis;
bitset<800100>C;
vector<int> adj[400100];
void AE(int a,int b){
    adj[a].push_back(b);
    adj[b].push_back(a);
}
set<pair<int,int>>st;
int main(){
    cin.tie(0)->sync_with_stdio(0);
    int n,w;
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>X[i]>>Y[i];
    cin>>w;
    for(int i=1;i<=w;i++){
        int a,b;
        cin>>a>>b;
        if(X[a]==X[b]){
            if(Y[a]>Y[b])swap(a,b);
            side[a][2][1]=i;
            side[a][2][0]=i+w;
            side[b][0][0]=i;
            side[b][0][1]=i+w;
            Xof[i]=X[a];
            st.insert({Xof[i],i});
        } else {
            if(X[a]>X[b])swap(a,b);
            side[a][1][0]=i;
            side[a][1][1]=i+w;
            side[b][3][1]=i;
            side[b][3][0]=i+w;
            Xof[i]=1e9;
        }
    }
    for(int i=1;i<=n;i++)
        for(int j=0;j<4;j++) if(side[i][j][1])
            for(int k=(j+1)%4;;k=(k+1)%4) if(side[i][k][0]){
                AE(side[i][k][0],side[i][j][1]);break;}
    deque<int>Q;
    memset(lev,7,sizeof lev);
    while(1){
        if(st.empty())break;
        int K=st.begin()->second;
        Q.push_back(K);
        lev[K]=0;
        while(Q.size()){
            int x=Q.front();Q.pop_front();
            if(vis[x])continue;
            if(x<=w)st.erase({Xof[x],x});
            vis[x]=1;
            for(auto y:adj[x])
                if(lev[y]>lev[x])
                    Q.push_front(y),lev[y]=lev[x];
            adj[x].clear();
            int k=(x>w?x-w:x+w);
            if(lev[k]>lev[x]+1)
                lev[k]=lev[x]+1,Q.push_back(k);
        }
    }
    vector<int>v;
    for(int i=1;i<=w;i++)
        if(lev[i]==lev[i+w])
            v.push_back(i);
    cout<<v.size()<<'\n';
    for(auto i:v)
        cout<<i<<'\n';
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 3 / 3
• Subtask 5: 10 / 10
• Subtask 6: 3 / 3
• Subtask 7: 3 / 3
• Subtask 8: 3 / 3
• Subtask 9: 3 / 3
• Subtask 10: 9 / 9
• Subtask 11: 9 / 9
• Subtask 12: 9 / 9
• Subtask 13: 9 / 9
• Subtask 14: 9 / 9