Submission #145562

#	Time	Username	Problem	Language	Result	Execution time	Memory
145562		surface03	문명 (KOI17_civilization)	C++14	100 / 100	462 ms	63032 KiB

civilization

#include<bits/stdc++.h>
 
const int LM=2005;
const int KLM=(int)1e5+1;
 
int N,K,G[LM][LM],gCnt,group[KLM];
int ans, now;
int fr,re;
int dr[]={1,-1,0,0},dc[]={0,0,1,-1};
struct Civil{
    int r,c,lev;
}que[LM*LM];
void ffill(int r,int c){
    if(G[r][c]>=0)return;
    G[r][c]=gCnt;
    que[re++]={r,c,0};
    for(int k=0;k<4;k++){
        ffill(r+dr[k],c+dc[k]);
    }
}
void input(){
    scanf("%d%d",&N,&K);
    int i,j,r,c;
    for(i=0;i<K;i++){
        scanf("%d%d",&r,&c);
        G[r][c]=-1;
    }
    for(i=1;i<=N;i++)for(j=1;j<=N;j++){
        if(G[i][j]<0){
            gCnt++;
            ffill(i,j);
        }
    }
    for(i=1;i<=gCnt;i++)group[i]=i;
}
int Find(int n){
    if(n==group[n])return n;
    return group[n]=Find(group[n]);
}
int push(int r,int c,int lev){
    if(r<1||r>N||c<1||c>N||G[r][c])return 0;
    G[r][c]=now;
    que[re++]={r,c,lev};
    for(int k=0;k<4;k++){
        int nr=r+dr[k],nc=c+dc[k];
        if(nr<1||nr>N||nc<1||nc>N)continue;
        if(G[nr][nc]==0)continue;
        int next=Find(G[nr][nc]);
        if(now==next)continue;
        group[next]=now;
        gCnt--;
    }
    if(gCnt==1)ans=lev;
    return gCnt==1;
}
int BFS(){
    if(gCnt==1)return ans;
    while(fr<re){
        Civil&t=que[fr++];
        now=Find(G[t.r][t.c]);
        for(int k=0;k<4;k++){
            if(push(t.r+dr[k],t.c+dc[k],t.lev+1)){
                return ans;
            }
        }
    }
}
int main(){
    input();
    printf("%d\n",BFS());
}

Compilation message (stderr)

civilization.cpp: In function 'void input()':
civilization.cpp:22:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&N,&K);
     ~~~~~^~~~~~~~~~~~~~
civilization.cpp:25:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&r,&c);
         ~~~~~^~~~~~~~~~~~~~
civilization.cpp: In function 'int BFS()':
civilization.cpp:67:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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