Submission #148009

#	Time	Username	Problem	Language	Result	Execution time	Memory
148009		arnold518	문명 (KOI17_civilization)	C++14	0 / 100	4 ms	888 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], col[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);
    par[x]=y;
}

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

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;
    for(i=1; i<=K; i++)
    {
        int y, x;
        scanf("%d%d", &y, &x);
        A[y][x]=-1;
        Q.push({y, x});
    }

    for(i=1; i<=N; i++) for(j=1; j<=N; j++)
    {
        if(A[i][j]!=-1) continue;
        dfs(i, j);
        cnt++;
    }

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

    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 'void dfs(int, int)':
civilization.cpp:28:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j;
            ^
civilization.cpp: In function 'int main()':
civilization.cpp:45:15: warning: unused variable 'k' [-Wunused-variable]
     int i, j, k;
               ^
civilization.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &N, &K);
     ~~~~~^~~~~~~~~~~~~~~~
civilization.cpp:52:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &y, &x);
         ~~~~~^~~~~~~~~~~~~~~~

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