Submission #66394

#	Time	Username	Problem	Language	Result	Execution time	Memory
66394		ansol4328	문명 (KOI17_civilization)	C++98	54 / 100	1056 ms	38144 KiB

civilization

#include<stdio.h>
#include<memory.h>
#include<queue>

using namespace std;

int n, k;
int visit[2002][2002];

int p[4000002];
int cnt;
bool st[4000002];
void setup(int a)
{
    cnt=a;
    memset(p,-1,sizeof(p));
    memset(st,false,sizeof(st));
}
int f(int v)
{
    if(p[v]==-1) return v;
    p[v]=f(p[v]);
    return p[v];
}
void u(int v1, int v2) // v2 subtree -> v1 subtree
{
    v1=f(v1);
    v2=f(v2);
    if(v1==v2) return;
    if(st[v2]) cnt--;
    p[v2]=v1;
}

queue<int> Q;

int main()
{
    scanf("%d %d",&n,&k);
    setup(k);
    for(int i=0 ; i<k ; i++)
    {
        int x, y;
        scanf("%d %d",&y,&x);
        st[(y-1)*n+x-1]=true;
        Q.push((y-1)*n+x-1);
        visit[y][x]=1;
    }
    int res=1;
    int dy[4]={-1,0,1,0};
    int dx[4]={0,1,0,-1};
    while(cnt!=1)
    {
        int y=Q.front()/n+1;
        int x=Q.front()%n+1;
        Q.pop();
        res=max(res,visit[y][x]);
        for(int i=0 ; i<4 ; i++)
        {
            if(!(y+dy[i]>=1 && y+dy[i]<=n && x+dx[i]>=1 && x+dx[i]<=n)) continue;
            if(visit[y+dy[i]][x+dx[i]]==0)
            {
                visit[y+dy[i]][x+dx[i]]=visit[y][x]+1;
                u((y-1)*n+x-1,(y+dy[i]-1)*n+x+dx[i]-1);
                Q.push((y+dy[i]-1)*n+x+dx[i]-1);
            }
            else if(visit[y+dy[i]][x+dx[i]]<visit[y][x]+1)
            {
                u((y-1)*n+x-1,(y+dy[i]-1)*n+x+dx[i]-1);
                res=max(res,visit[y][x]);
            }
            if(cnt==1) break;
        }
    }
    printf("%d",res-1);
    return 0;
}

Compilation message (stderr)

civilization.cpp: In function 'int main()':
civilization.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&k);
     ~~~~~^~~~~~~~~~~~~~~
civilization.cpp:43:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&y,&x);
         ~~~~~^~~~~~~~~~~~~~~

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