Submission #152344

#	Time	Username	Problem	Language	Result	Execution time	Memory
152344		arnold518	문명 (KOI17_civilization)	C++14	100 / 100	824 ms	43068 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 INF = 2e9;

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

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

int par[MAXN*MAXN+10];
int f(int y, int x) { y--; x--; return y*N+x; }
int Find(int x) { return x==par[x]?x:(par[x]=Find(par[x])); }

int main()
{
    int i, j;

    scanf("%d%d", &N, &K);
    for(i=0; i<N*N; i++) par[i]=i;
    for(i=1; i<=N; i++) for(j=1; j<=N; j++) A[i][j]=INF;

    queue<pii> Q;
    for(i=1; i<=K; i++)
    {
        int y, x;
        scanf("%d%d", &y, &x);
        A[y][x]=0; Q.push({y, x});
    }
    K=0;
    int ans=0;
    for(ans=0; ; ans++)
    {
        int sz=Q.size();
        while(sz--)
        {
            pii now=Q.front(); Q.pop();
            vis[now.first][now.second]=1; K++;
            for(i=0; i<4; i++)
            {
                pii nxt={now.first+dy[i], now.second+dx[i]};
                if(!(1<=nxt.first && nxt.first<=N && 1<=nxt.second && nxt.second<=N)) continue;

                if(vis[nxt.first][nxt.second])
                {
                    int a=Find(f(now.first, now.second)), b=Find(f(nxt.first, nxt.second));
                    if(a!=b) K--;
                    par[a]=b;
                }
                else if(A[nxt.first][nxt.second]==INF)
                {
                    A[nxt.first][nxt.second]=A[now.first][now.second]+1;
                    Q.push(nxt);
                }
            }
        }
        if(K==1) return !printf("%d", ans);
    }
}

Compilation message (stderr)

civilization.cpp: In function 'int main()':
civilization.cpp:26:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &N, &K);
     ~~~~~^~~~~~~~~~~~~~~~
civilization.cpp:34:14: 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: 46 / 46