#include "bits/stdc++.h"
using namespace std;
const int MAXN = 3e4+5;
vector<set< int> > adj(MAXN);
vector< vector < int > > doges(MAXN);
int dp[MAXN];
map< pair<int, int>, bool > done;
bool visited[MAXN];
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
int goal, begin;
for(int i = 0; i < m; i++)
{
pair<int, int> temp;
cin >> temp.first >> temp.second;
if(i == 1)
goal = temp.first;
else if(i == 0)
begin = temp.first;
doges[temp.first].push_back(temp.second);
}
for(int i = 0; i <= n; i++) {
dp[i] = 1e9;
visited[i] = false;
}
visited[begin] = false;
dp[begin] = 0;
set< pair<int, int> > curr;
curr.insert({0, begin});
int ans = 1e9;
while(!curr.empty())
{
pair<int, int> temp = *(curr.begin());
int v = temp.second;
int len = temp.first;
// cout << v << "\n";
curr.erase(curr.begin());
if(v == goal)
ans = min(len, ans);
if(!visited[v]) // Add its edges
{
for(int doge : doges[v])
{
//if(v == 4)
// cout << doge << "\n";
//if(done[{v, doge}])
//continue;
int curr = v;
while(curr + doge < n)
{
if(done[{curr, curr + doge}])
break;
done[{curr, doge}] = true;
adj[curr].insert(curr + doge);
curr += doge;
}
curr = v;
while(curr - doge >= 0)
{
if(done[{curr, curr - doge}])
break;
//if(v == 4)
//cout << curr << "\n";
done[{curr, curr - doge}] = true;
adj[curr].insert(curr - doge);
curr -= doge;
}
}
}
visited[v] = true;
for(int e : adj[v])
{
if(dp[e] > len + 1)
{
curr.erase({dp[e], e});
dp[e] = len + 1;
curr.insert({dp[e], e});
}
}
adj[v].clear();
dp[v] = 1e9;
}
cout << ans << "\n";
}
Compilation message
skyscraper.cpp: In function 'int main()':
skyscraper.cpp:45:9: warning: 'goal' may be used uninitialized in this function [-Wmaybe-uninitialized]
45 | if(v == goal)
| ^~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2388 KB |
Output is correct |
2 |
Correct |
1 ms |
2388 KB |
Output is correct |
3 |
Correct |
2 ms |
2388 KB |
Output is correct |
4 |
Incorrect |
1 ms |
2388 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2388 KB |
Output is correct |
2 |
Correct |
1 ms |
2388 KB |
Output is correct |
3 |
Correct |
1 ms |
2388 KB |
Output is correct |
4 |
Incorrect |
1 ms |
2388 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2388 KB |
Output is correct |
2 |
Correct |
2 ms |
2388 KB |
Output is correct |
3 |
Correct |
1 ms |
2388 KB |
Output is correct |
4 |
Incorrect |
1 ms |
2452 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2388 KB |
Output is correct |
2 |
Correct |
1 ms |
2388 KB |
Output is correct |
3 |
Correct |
1 ms |
2388 KB |
Output is correct |
4 |
Incorrect |
1 ms |
2388 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2400 KB |
Output is correct |
2 |
Correct |
1 ms |
2388 KB |
Output is correct |
3 |
Correct |
1 ms |
2460 KB |
Output is correct |
4 |
Incorrect |
1 ms |
2388 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |