#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pp;
typedef pair<ll,ll> pll;
void read(int& x){ scanf("%d",&x); }
void read(ll& x){ scanf("%lld",&x); }
template<typename T,typename... Args>
void read(T& a,Args&... b){ read(a); read(b...); }
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define eb emplace_back
#define x first
#define y second
int n, m;
vector<int> b[30010];
const int Lim = 100;
const int V = 30000*(Lim + 1);
int dist[V];
vector<pp> edge[V];
vector<int> usable[30010];
int main()
{
read(n, m);
int tg = 0;
for(int i=0; i<m; ++i){
int b, p;
read(b, p);
if(i == 1) tg = b;
if(p <= Lim) ::b[p].pb(b);
else usable[b].pb(p);
}
for(int p=1; p<=Lim; ++p) if(b[p].size()){
for(int a:b[p]) edge[a].eb(p*n+a, 0);
for(int i=0; i<n; ++i){
if(i+p < n) edge[p*n+i].eb(p*n+(i+p), 1);
if(i-p >=0) edge[p*n+i].eb(p*n+(i-p), 1);
edge[p*n+i].eb(i, 0);
}
}
fill(dist+1, dist+V, 1e9);
priority_queue<pp> pq;
pq.emplace(0, 0);
while(pq.size()){
int md, x; tie(md, x) = pq.top(); pq.pop();
md = -md;
if(md != dist[x]) continue;
auto relax = [&](int y, int d){
if(dist[y] > d){
dist[y] = d;
pq.emplace(-d, y);
}
};
for(auto et:edge[x]) relax(et.x, md+et.y);
if(x < n){
for(int p:usable[x]){
for(int i=1;;++i) if(x-p*i>=0) relax(x-p*i, md+i); else break;
for(int i=1;;++i) if(x+p*i<n) relax(x+p*i, md+i); else break;
}
}
}
int ans = dist[tg];
if(ans == 1e9) ans = -1;
printf("%d\n", ans);
return 0;
}
Compilation message
skyscraper.cpp: In function 'void read(int&)':
skyscraper.cpp:6:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
void read(int& x){ scanf("%d",&x); }
~~~~~^~~~~~~~~
skyscraper.cpp: In function 'void read(ll&)':
skyscraper.cpp:7:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
void read(ll& x){ scanf("%lld",&x); }
~~~~~^~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
75 ms |
84728 KB |
Output is correct |
2 |
Correct |
77 ms |
84840 KB |
Output is correct |
3 |
Correct |
77 ms |
84840 KB |
Output is correct |
4 |
Correct |
73 ms |
84840 KB |
Output is correct |
5 |
Correct |
72 ms |
84840 KB |
Output is correct |
6 |
Correct |
77 ms |
84988 KB |
Output is correct |
7 |
Correct |
76 ms |
84988 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
73 ms |
84992 KB |
Output is correct |
2 |
Correct |
75 ms |
84992 KB |
Output is correct |
3 |
Correct |
70 ms |
84992 KB |
Output is correct |
4 |
Correct |
71 ms |
84992 KB |
Output is correct |
5 |
Correct |
72 ms |
84992 KB |
Output is correct |
6 |
Correct |
69 ms |
85000 KB |
Output is correct |
7 |
Correct |
74 ms |
85100 KB |
Output is correct |
8 |
Incorrect |
80 ms |
85104 KB |
Output isn't correct |
9 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
77 ms |
85104 KB |
Output is correct |
2 |
Correct |
76 ms |
85104 KB |
Output is correct |
3 |
Correct |
74 ms |
85104 KB |
Output is correct |
4 |
Correct |
68 ms |
85104 KB |
Output is correct |
5 |
Correct |
77 ms |
85104 KB |
Output is correct |
6 |
Correct |
75 ms |
85104 KB |
Output is correct |
7 |
Correct |
74 ms |
85104 KB |
Output is correct |
8 |
Incorrect |
76 ms |
85116 KB |
Output isn't correct |
9 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
83 ms |
85116 KB |
Output is correct |
2 |
Correct |
69 ms |
85116 KB |
Output is correct |
3 |
Correct |
75 ms |
85116 KB |
Output is correct |
4 |
Correct |
77 ms |
85116 KB |
Output is correct |
5 |
Correct |
79 ms |
85116 KB |
Output is correct |
6 |
Correct |
71 ms |
85116 KB |
Output is correct |
7 |
Correct |
69 ms |
85116 KB |
Output is correct |
8 |
Incorrect |
70 ms |
85116 KB |
Output isn't correct |
9 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
95 ms |
85116 KB |
Output is correct |
2 |
Correct |
78 ms |
85116 KB |
Output is correct |
3 |
Correct |
77 ms |
85116 KB |
Output is correct |
4 |
Correct |
77 ms |
85116 KB |
Output is correct |
5 |
Correct |
77 ms |
85116 KB |
Output is correct |
6 |
Correct |
84 ms |
85116 KB |
Output is correct |
7 |
Correct |
210 ms |
85116 KB |
Output is correct |
8 |
Incorrect |
76 ms |
85116 KB |
Output isn't correct |
9 |
Halted |
0 ms |
0 KB |
- |