#include <bits/stdc++.h>
#include <vector>
#include <queue>
using namespace std;
typedef long long ll;
ll h[5005];
int n;
bool check(int i)
{
if (h[i-2] <= h[i-1] && h[i-1] <= h[i]) return 1;
if (h[i-2] >= h[i-1] && h[i-1] >= h[i]) return 1;
return 0;
}
struct seg {
ll hmax, hmin;
bool dir;
};
int hashState (int x, int y)
{
return (n + 1) * x + y;
}
struct edge {
int to; ll cost;
};
seg s[5005];
vector<vector<edge>> adj;
vector<ll> dist;
bool unhash (int x)
{
int f = x % (n + 1);
int s = x / (n + 1);
if (f == s) return 1;
if (s == f + 1) return 1;
return 0;
}
ll dijsktra ()
{
priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> q;
q.push({0, hashState(1, n-1)});
dist[hashState(1, n - 1)] = 0;
ll ans = -1;
while (!q.empty())
{
pair<ll, int> crt = q.top();
q.pop();
// cout << crt.first << '\n';
// cout << crt.second / (n + 1) << ' ' << crt.second % (n + 1) << '\n';
if (unhash(crt.second))
{
ans = crt.first;
break;
}
if (crt.first > dist[crt.second]) continue;
for (auto to : adj[crt.second])
{
// cout << dist[to.to] << ' ';
if (dist[to.to] > dist[crt.second] + to.cost)
{
q.push({dist[crt.second] + to.cost, to.to});
dist[to.to] = dist[crt.second] + to.cost;
}
}
}
return ans;
}
int main ()
{
cin >> n;
for (int i = 1; i <= n; i++)
{
cin >> h[i];
if (i > 2 && check(i))
{
n--;
i--;
h[i] = h[i+1];
h[i+1] = 0;
}
}
dist.resize((n + 2) * (n + 1) + 2, 1e18);
adj.resize((n + 2) * (n + 1) + 3);
for (int i = 1; i < n; i++)
{
s[i] = {max(h[i], h[i+1]), min(h[i], h[i+1])};
if (h[i] < h[i+1]) s[i].dir = 1;
// cout << s[i].hmin << ' ' << s[i].hmax << '\n';
}
for (int i = 1; i <= n; i++)
{
for (int j = 1; j < n; j++)
{
if (s[j].hmin > h[i] || s[j].hmax < h[i]) continue;
// cout << i << ' ' << j << ":\n";
if (h[i+1] >= s[j].hmin && h[i+1] <= s[j].hmax)
{
// cout << h[i+1] << ' ' << s[j].hmin << ' ' << s[j].hmax << '\n';
// cout << hashState(i, j) << ' ' << hashState(i + 1, j) << '\n';
adj[hashState(i, j)].push_back({hashState(i + 1, j), abs(h[i] - h[i+1])});
adj[hashState(i + 1, j)].push_back({hashState(i, j), abs(h[i] - h[i+1])});
}
if (i > 1 && h[i-1] >= s[j].hmin && h[i-1] <= s[j].hmax)
{
// cout << h[i-1] << ' ' << s[j].hmin << ' ' << s[j].hmax << '\n';
// cout << hashState(i, j) << ' ' << hashState(i - 1, j) << '\n';
adj[hashState(i, j)].push_back({hashState(i - 1, j), abs(h[i] - h[i-1])});
adj[hashState(i - 1, j)].push_back({hashState(i, j), abs(h[i] - h[i-1])});
}
if (h[j] >= s[i].hmin && h[j] <= s[i].hmax)
{
// cout << h[j] << ' ' << s[i].hmin << ' ' << s[i].hmax << '\n';
// cout << hashState(i, j) << ' ' << hashState(j, i) << '\n';
adj[hashState(i, j)].push_back({hashState(j, i), abs(h[j] - h[i])});
adj[hashState(j, i)].push_back({hashState(i, j), abs(h[j] - h[i])});
}
if (i > 1 && h[j] >= s[i-1].hmin && h[j] <= s[i-1].hmax)
{
// cout << h[j] << ' ' << s[i-1].hmin << ' ' << s[i-1].hmax << '\n';
// cout << hashState(i, j) << ' ' << hashState(j, i-1) << '\n';
adj[hashState(i, j)].push_back({hashState(j, i-1), abs(h[j] - h[i])});
adj[hashState(j, i-1)].push_back({hashState(i, j), abs(h[j] - h[i])});
}
if (h[j+1] >= s[i].hmin && h[j+1] <= s[i].hmax)
{
// cout << h[j+1] << ' ' << s[i].hmin << ' ' << s[i].hmax << '\n';
// cout << hashState(i, j) << ' ' << hashState(j+1, i) << '\n';
adj[hashState(i, j)].push_back({hashState(j+1, i), abs(h[j+1] - h[i])});
adj[hashState(j+1, i)].push_back({hashState(i, j), abs(h[j+1] - h[i])});
}
if (i > 1 && h[j+1] >= s[i-1].hmin && h[j+1] <= s[i-1].hmax)
{
// cout << h[j+1] << ' ' << s[i-1].hmin << ' ' << s[i-1].hmax << '\n';
// cout << hashState(i, j) << ' ' << hashState(j+1, i-1) << '\n';
adj[hashState(i, j)].push_back({hashState(j+1, i-1), abs(h[j+1] - h[i])});
adj[hashState(j+1, i-1)].push_back({hashState(i, j), abs(h[j+1] - h[i])});
}
}
}
/* for (int i = 1; i <= (n + 1) * n; i++)
{
cout << i / (n + 1) << ' ' << i % (n + 1) << ":\n";
for (auto to : adj[i])
cout << " " << to.to / (n + 1) << ' ' <<
to.to % (n + 1) << ' ' << to.cost << '\n';
}*/
cout << dijsktra() << '\n';
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
1104 KB |
Output is correct |
| 2 |
Correct |
10 ms |
6228 KB |
Output is correct |
| 3 |
Correct |
134 ms |
65720 KB |
Output is correct |
| 4 |
Execution timed out |
893 ms |
524288 KB |
Time limit exceeded |
| 5 |
Runtime error |
211 ms |
524288 KB |
Execution killed with signal 9 |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
340 KB |
Output is correct |
| 2 |
Correct |
1 ms |
468 KB |
Output is correct |
| 3 |
Correct |
3 ms |
2260 KB |
Output is correct |
| 4 |
Correct |
2 ms |
1236 KB |
Output is correct |
| 5 |
Correct |
16 ms |
10708 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
2004 KB |
Output is correct |
| 2 |
Correct |
20 ms |
13664 KB |
Output is correct |
| 3 |
Correct |
589 ms |
253704 KB |
Output is correct |
| 4 |
Runtime error |
558 ms |
524288 KB |
Execution killed with signal 9 |
| 5 |
Runtime error |
530 ms |
524288 KB |
Execution killed with signal 9 |
| 6 |
Runtime error |
243 ms |
524288 KB |
Execution killed with signal 9 |
| 7 |
Runtime error |
273 ms |
524288 KB |
Execution killed with signal 9 |
| 8 |
Runtime error |
201 ms |
524288 KB |
Execution killed with signal 9 |
| 9 |
Runtime error |
208 ms |
524288 KB |
Execution killed with signal 9 |
| 10 |
Runtime error |
193 ms |
524288 KB |
Execution killed with signal 9 |
