#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> ii;
int n,m,d[2005][2005];
bool Visited[30005],Free[2005][2005];
vector<int> g[30005];
queue<ii> Q;
int main()
{
ios_base::sync_with_stdio(false);
//freopen("TEST.INP","r",stdin);
cin>>n>>m;
int pos,step;
while(m--)
{
cin>>pos>>step;
g[pos+1].push_back(step);
}
for(int i=0; i<g[1].size(); i++)
{
Free[1][g[1][i]]=true;
Q.push(ii(1,g[1][i]));
}
while(Q.size()>0)
{
int u=Q.front().first;
int v=Q.front().second;
Q.pop();
if(u==2)
{
cout<<d[u][v];
return 0;
}
if(Visited[u]==false)
{
Visited[u]=true;
for(int i=0; i<g[u].size(); i++)
{
if(u-g[u][i]>=1&&Free[u-g[u][i]][g[u][i]]==false)
{
Free[u-g[u][i]][g[u][i]]=true;
d[u-g[u][i]][g[u][i]]=d[u][v]+1;
Q.push(ii(u-g[u][i],g[u][i]));
}
if(u+g[u][i]<=n&&Free[u+g[u][i]][g[u][i]]==false)
{
Free[u+g[u][i]][g[u][i]]=true;
d[u+g[u][i]][g[u][i]]=d[u][v]+1;
Q.push(ii(u+g[u][i],g[u][i]));
}
}
}
if(u-v>=1&&Free[u-v][v]==false)
{
Free[u-v][v]=true;
d[u-v][v]=d[u][v]+1;
Q.push(ii(u-v,v));
}
if(u+v<=n&&Free[u+v][v]==false)
{
Free[u+v][v]=true;
d[u+v][v]=d[u][v]+1;
Q.push(ii(u+v,v));
}
}
cout<<-1;
}
Compilation message
skyscraper.cpp: In function 'int main()':
skyscraper.cpp:21:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0; i<g[1].size(); i++)
~^~~~~~~~~~~~
skyscraper.cpp:39:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0; i<g[u].size(); i++)
~^~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
1016 KB |
Output is correct |
2 |
Incorrect |
3 ms |
1128 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
1208 KB |
Output is correct |
2 |
Incorrect |
3 ms |
1208 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
1208 KB |
Output is correct |
2 |
Incorrect |
2 ms |
1332 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
1332 KB |
Output is correct |
2 |
Incorrect |
2 ms |
1332 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
1332 KB |
Output is correct |
2 |
Incorrect |
3 ms |
1332 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |