#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
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);
~~~~~^~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
760 KB |
Output is correct |
2 |
Correct |
3 ms |
760 KB |
Output is correct |
3 |
Correct |
3 ms |
760 KB |
Output is correct |
4 |
Correct |
3 ms |
760 KB |
Output is correct |
5 |
Correct |
3 ms |
760 KB |
Output is correct |
6 |
Correct |
4 ms |
760 KB |
Output is correct |
7 |
Correct |
3 ms |
888 KB |
Output is correct |
8 |
Correct |
3 ms |
888 KB |
Output is correct |
9 |
Correct |
4 ms |
888 KB |
Output is correct |
10 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
11 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
760 KB |
Output is correct |
2 |
Correct |
3 ms |
760 KB |
Output is correct |
3 |
Correct |
3 ms |
760 KB |
Output is correct |
4 |
Correct |
3 ms |
760 KB |
Output is correct |
5 |
Correct |
3 ms |
760 KB |
Output is correct |
6 |
Correct |
4 ms |
760 KB |
Output is correct |
7 |
Correct |
3 ms |
888 KB |
Output is correct |
8 |
Correct |
3 ms |
888 KB |
Output is correct |
9 |
Correct |
4 ms |
888 KB |
Output is correct |
10 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
11 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
760 KB |
Output is correct |
2 |
Correct |
3 ms |
760 KB |
Output is correct |
3 |
Correct |
3 ms |
760 KB |
Output is correct |
4 |
Correct |
3 ms |
760 KB |
Output is correct |
5 |
Correct |
3 ms |
760 KB |
Output is correct |
6 |
Correct |
4 ms |
760 KB |
Output is correct |
7 |
Correct |
3 ms |
888 KB |
Output is correct |
8 |
Correct |
3 ms |
888 KB |
Output is correct |
9 |
Correct |
4 ms |
888 KB |
Output is correct |
10 |
Incorrect |
2 ms |
376 KB |
Output isn't correct |
11 |
Halted |
0 ms |
0 KB |
- |