Submission #148019

#	Time	Username	Problem	Language	Result	Execution time	Memory
148019		arnold518	문명 (KOI17_civilization)	C++14	54 / 100	1078 ms	52356 KiB

civilization

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 2000;
const int MAXK = 1e5;

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

int N, K, A[MAXN+10][MAXN+10];

int conv(int y, int x) { return (y-1)*N+(x-1); }

int par[MAXN*MAXN+10], Rank[MAXN*MAXN+10], cnt=0, ans;
int Find(int x) { return x==par[x]?x:par[x]=Find(par[x]); }
void Union(int x, int y)
{
    x=Find(x); y=Find(y);
    if(Rank[x]<Rank[y]) swap(x, y);
    if(Rank[x]==Rank[y]) Rank[x]++;
    par[y]=x;
}


struct Queue { int y, x; };
queue<Queue> Q;

int main()
{
    int i, j, k;

    scanf("%d%d", &N, &K);
    for(i=0; i<N*N; i++) par[i]=i, Rank[i]=1;
    for(i=1; i<=K; i++)
    {
        int y, x;
        scanf("%d%d", &y, &x);
        A[y][x]=1;
        Q.push({y, x}); cnt++;
    }

    for(i=1; i<=N; i++) for(j=1; j<=N; j++)
    {
        if(!A[i][j]) continue;
        for(k=0; k<4; k++)
        {
            int ny=i+dy[k], nx=j+dx[k];
            if(!(1<=ny && ny<=N && 1<=nx && nx<=N)) continue;
            if(!A[ny][nx]) continue;
            if(Find(conv(ny, nx))!=Find(conv(i, j)))
            {
                cnt--;
                Union(conv(ny, nx), conv(i, j));
            }
        }
    }

    //for(i=1; i<=N; i++) { for(j=1; j<=N; j++) printf("%d ", A[i][j]); printf("\n"); }
    //printf("\n");

    if(cnt==1) return !printf("0");

    while(!Q.empty())
    {
        int sz=Q.size(); ans++;
        while(sz--)
        {
            Queue T=Q.front(); Q.pop();
            for(i=0; i<4; i++)
            {
                int ny=T.y+dy[i], nx=T.x+dx[i];
                if(!(1<=ny && ny<=N && 1<=nx && nx<=N)) continue;
                if(Find(conv(ny, nx))==Find(conv(T.y, T.x))) continue;
                if(A[ny][nx]==0)
                {
                    Union(conv(ny, nx), conv(T.y, T.x));
                    A[ny][nx]=1;
                    Q.push({ny, nx});
                }
                else
                {
                    cnt--;
                    Union(conv(ny, nx), conv(T.y, T.x));
                }
            }
        }

        sz=Q.size();
        while(sz--)
        {
            Queue T=Q.front(); Q.pop(); Q.push(T);
            for(i=0; i<4; i++)
            {
                int ny=T.y+dy[i], nx=T.x+dx[i];
                if(!(1<=ny && ny<=N && 1<=nx && nx<=N)) continue;
                if(Find(conv(ny, nx))==Find(conv(T.y, T.x))) continue;
                if(A[ny][nx]!=0)
                {
                    cnt--;
                    Union(conv(ny, nx), conv(T.y, T.x));
                }
            }
        }
        //for(i=1; i<=N; i++) { for(j=1; j<=N; j++) printf("%d ", A[i][j]); printf("\n"); }
        //printf("-> %d\n", cnt);
        if(cnt==1) return !printf("%d", ans);
    }
}

Compilation message (stderr)

civilization.cpp: In function 'int main()':
civilization.cpp:36:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &N, &K);
     ~~~~~^~~~~~~~~~~~~~~~
civilization.cpp:41:14: 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