제출 #977556

#제출 시각아이디문제언어결과실행 시간메모리
977556faricaMecho (IOI09_mecho)C++14
25 / 100
1099 ms6744 KiB
#include <bits/stdc++.h> #define int long long using namespace std; const int MAX_N = 4e5 + 5; int n, s, dist[800][800], sx, sy; string grid[800]; bool test(int m) { priority_queue<pair<int, pair<int,int>>>pq; vector<vector<bool>>visited(n, vector<bool>(n, 0)); pq.push({0, {sx, sy}}); while(!pq.empty()) { int x = pq.top().second.first, y = pq.top().second.second, cnt = -1 * pq.top().first; pq.pop(); if(visited[x][y]) continue; visited[x][y] = 1; if(grid[x][y] == 'D') return true; int cost = ((cnt+1) / s) + ((cnt+1) % s > 0 ? 1 : 0) + m; if(x && grid[x-1][y] != 'T' && dist[x-1][y] >= cost) pq.push({(cnt + 1) * -1, {x-1, y}}); if(y && grid[x][y-1] != 'T' && dist[x][y-1] >= cost) pq.push({(cnt + 1) * -1, {x, y-1}}); if(x+1<n && grid[x+1][y] != 'T' && dist[x+1][y] >= cost) pq.push({(cnt + 1) * -1, {x+1, y}}); if(y+1<n && grid[x][y+1] != 'T' && dist[x][y+1] >= cost) pq.push({(cnt + 1) * -1, {x, y+1}}); } return false; } void solve() { cin >> n >> s; queue<pair<int,int>>q; for(int i=0; i<n; ++i) { cin >> grid[i]; for(int j=0; j<n; ++j) { dist[i][j] = -1; if(grid[i][j] == 'H') { q.push({i, j}); dist[i][j] = 0; } else if(grid[i][j] == 'M') sx=i, sy=j; } } while(!q.empty()) { int i = q.front().first, j = q.front().second; q.pop(); if(i && dist[i-1][j] == -1 && grid[i-1][j] != 'T' && grid[i-1][j] != 'M') { dist[i-1][j] = dist[i][j] + 1; q.push({i-1, j}); } if(j && dist[i][j-1] == -1 && grid[i][j-1] != 'T' && grid[i][j-1] != 'M') { dist[i][j-1] = dist[i][j] + 1; q.push({i, j-1}); } if(i<n-1 && dist[i+1][j] == -1 && grid[i+1][j] != 'T' && grid[i+1][j] != 'M') { dist[i+1][j] = dist[i][j] + 1; q.push({i+1, j}); } if(j<n-1 && dist[i][j+1] == -1 && grid[i][j+1] != 'T' && grid[i][j+1] != 'M') { dist[i][j+1] = dist[i][j] + 1; q.push({i, j+1}); } } if(!test(0)) { cout << -1 << endl; return; } int l=0, r=n*n, mid; while(l<=r) { mid = (l+r)/2; if(test(mid)) l = mid + 1; else r = mid - 1; } cout << l - 1 << endl; } signed main() { ios::sync_with_stdio(false); cin.tie(0); cout.tie(0); int t = 1; while(t--) solve(); return 0; }
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