# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1066048 | belgianbot | Mecho (IOI09_mecho) | C++17 | 241 ms | 65536 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#define se second
#define fi first
using namespace std;
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
int N, S; cin >> N >> S;
vector<string> grid(N);
for (int i = 0; i < N; i++) {
cin >> grid[i];
}
int start, end;
vector<int> dist(N * N, INT_MAX);
vector<vector<int>> adj(N * N);
queue<pair<int,int>> hives;
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++) {
if (grid[i][j] == 'H') {
hives.push({i * N + j, 1});
dist[i * N + j] = 0;
}
else if (grid[i][j] == 'M') start = i * N + j;
else if (grid[i][j] == 'D') end = i * N + j;
if (grid[i][j] == 'H' || grid[i][j] == 'T') continue;
if (i && (grid[i - 1][j] == 'D' || grid[i - 1][j] == 'H' || grid[i - 1][j] == 'M' || grid[i - 1][j] == 'G')) adj[i * N - N + j].push_back(i * N + j);
if (j && (grid[i][j-1] == 'D' || grid[i][j-1] == 'H' || grid[i][j-1] == 'M' || grid[i][j-1] == 'G')) adj[i * N + j-1].push_back(i * N + j);
if (i != N - 1 && (grid[i + 1][j] == 'D' || grid[i + 1][j] == 'H' || grid[i + 1][j] == 'M' || grid[i + 1][j] == 'G')) adj[i * N + N + j].push_back(i * N + j);
if (j != N - 1 && (grid[i][j+1] == 'D' || grid[i][j+1] == 'H' || grid[i][j+1] == 'M' || grid[i][j+1] == 'G')) adj[i * N + j+1].push_back(i * N + j);
}
}
while (!hives.empty()) {
auto x = hives.front(); hives.pop();
for (int y : adj[x.fi]) {
if (dist[y] == INT_MAX && grid[y / N][y % N] != 'D'){
hives.push({y, x.se + 1});
dist[y] = x.se;
}
}
}
int maxi = 0;
for (int x : adj[end]) maxi = max(maxi, dist[x]);
vector<bool> pro;
int l = 0, r = N * N / 2 + N;
while (l <= r) {
int mid = l + (r - l) / 2;
pro.clear(); pro.resize(N * N, false);
queue<pair<int,int>> q;
q.push({mid * S, start});
bool won = false;
while (!q.empty() && !won) {
auto u = q.front(); q.pop();
pro[u.se] = true;
for (int x : adj[u.se]) {
if (x == end) {won = true; break;}
if (!pro[x] && (u.fi + 1) / S < dist[x] && (u.fi + 1) / S <= maxi) q.push({u.fi + 1, x});
}
}
if (won) l = mid + 1;
else r = mid - 1;
}
cout << l - 1 << '\n';
return 0;
}
Compilation message (stderr)
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