Submission #59109

#	Time	Username	Problem	Language	Result	Execution time	Memory
59109		andy627	문명 (KOI17_civilization)	C++17	54 / 100	1080 ms	55988 KiB

civilization

#include <stdio.h>
#include <queue>
#include <algorithm>
#define INF 2e9
using namespace std;

int par[2002*2002];
int dist[2002][2002],num[2002][2002];
bool is_gone[2002][2002];
queue<int> qx,qy;

int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};

int find_(int x){
    if(par[x]==x) return x;
    return par[x]=find_(par[x]);
}

int main(){
    int n,k;

    scanf("%d %d",&n,&k);

    int pos=0;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=n;j++) dist[i][j]=INF,num[i][j]=++pos;
    for(int i=1;i<=pos;i++) par[i]=i;

    for(int i=1;i<=k;i++){
        int a,b;
        scanf("%d %d",&a,&b);
        dist[a][b]=0;
        qx.push(a); qy.push(b);
    }

    int ans=0,cnt=0;
    for(;;ans++){
        while(!qx.empty()){
            int px=qx.front(); qx.pop();
            int py=qy.front(); qy.pop();

            if(dist[px][py]!=ans){
                qx.push(px); qy.push(py);
                break;
            }

            is_gone[px][py]=1; cnt++;
            for(int d=0;d<4;d++){
                int nx=px+dx[d];
                int ny=py+dy[d];

                if(nx<1 || nx>n || ny<1 || ny>n) continue;
                if(is_gone[nx][ny]){
                    int root_a=find_(num[nx][ny]);
                    int root_b=find_(num[px][py]);

                    if(root_a!=root_b) cnt--;
                    par[root_b]=root_a;
                }
                else if(dist[nx][ny]==INF){
                    dist[nx][ny]=dist[px][py]+1;
                    qx.push(nx); qy.push(ny);
                }
            }
        }
        if(cnt==1) break;
    }

    printf("%d\n",ans);

    return 0;
}

Compilation message (stderr)

civilization.cpp: In function 'int main()':
civilization.cpp:23:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&k);
     ~~~~~^~~~~~~~~~~~~~~
civilization.cpp:32:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 19 / 19
• Subtask 2: 35 / 35
• Subtask 3: 0 / 46