제출 #977571

#제출 시각아이디문제언어결과실행 시간메모리
977571faricaMecho (IOI09_mecho)C++14
14 / 100
147 ms6616 KiB
#include <bits/stdc++.h> #define int long long using namespace std; const int MAX_N = 4e5 + 5; int n, s, dist[805][805], sx, sy, ex, ey; string grid[805]; bool test(int m) { queue<pair<int, pair<int,int>>>q; q.push({0, {sx, sy}}); vector<vector<bool>>visited(n, vector<bool>(n, 0)); while(!q.empty()) { int cnt = q.front().first, x = q.front().second.first, y = q.front().second.second; q.pop(); if(visited[x][y]) continue; visited[x][y] = 1; ++cnt; int cost = cnt / s + (cnt % s > 0 ? 1 : 0) + m; if(x && dist[x-1][y] >= cost && grid[x-1][y] == 'G') q.push({cnt, {x-1, y}}); if(y && dist[x][y-1] >= cost && grid[x][y-1] == 'G') q.push({cnt, {x, y-1}}); if(x+1<n && dist[x+1][y] >= cost && grid[x+1][y] == 'G') q.push({cnt, {x+1, y}}); if(y+1<n && dist[x][y+1] >= cost && grid[x][y+1] == 'G') q.push({cnt, {x, y+1}}); } if(ex && visited[ex-1][ey]) return true; if(ey && visited[ex][ey-1]) return true; if(ex+1<n && visited[ex+1][ey]) return true; if(ey+1<n && visited[ex][ey+1]) return true; 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; else if(grid[i][j] == 'D') ex=i, ey=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] != 'D') { 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] != 'D') { 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] != 'D') { 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] != 'D') { dist[i][j+1] = dist[i][j] + 1; q.push({i, j+1}); } } if(!test(0)) { cout << -1 << endl; return; } int l=0, r=dist[sx][sy]-1, 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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