Submission #977333

#	Time	Username	Problem	Language	Result	Execution time	Memory
977333		farica	Mecho (IOI09_mecho)	C++14	2 / 100	391 ms	65540 KiB

mecho

#include <bits/stdc++.h>
#define int long long

using namespace std;

const int MAX_N = 4e5 + 5;
const int MOD = 998244353;

void solve() {
    int n, s;
    cin >> n >> s;
    string grid[n];
    int sx=0, sy=0;
    vector<vector<int>>depth(n, vector<int>(n, -1));
    queue<pair<int,int>>q;
    for(int i=0; i<n; ++i) {
        cin >> grid[i];
        for(int j=0; j<n; ++j) {
            if(grid[i][j] == 'M') {
                sx=i;
                sy=j;
            }
            else if(grid[i][j] == 'H') {
                q.push({i, j});
                depth[i][j] = 0;
            }
        }
    }
    while(!q.empty()) {
        int x = q.front().first, y = q.front().second;
        q.pop();
        if(x && grid[x-1][y] != 'T' && depth[x-1][y] == -1) {
            depth[x-1][y] = depth[x][y] + 1;
            q.push({x-1, y});
        }
        if(y && grid[x][y-1] != 'T' && depth[x][y-1] == -1) {
            depth[x][y-1] = depth[x][y] + 1;
            q.push({x, y-1});
        }
        if(x+1<n && grid[x+1][y] != 'T' && depth[x+1][y] == -1) {
            depth[x+1][y] = depth[x][y] + 1;
            q.push({x+1, y});
        }
        if(y+1<n && grid[x][y+1] != 'T' && depth[x][y+1] == -1) {
            depth[x][y+1] = depth[x][y] + 1;
            q.push({x, y+1});
        }
    }
    priority_queue<pair<pair<int,int>, pair<int,int>>>pq;
    pq.push({{depth[sx][sy], 0}, {sx, sy}});
    while(!pq.empty()) {
        int t = pq.top().first.first, visited = pq.top().first.second, x = pq.top().second.first, y = pq.top().second.second;
        pq.pop();
        if(grid[x][y] == 'D') {
            cout << t << endl;
            return;
        }
        int new_t, cost = (visited+1)/s + ((visited+1) % s > 0 ? 1 : 0);
        if(x && grid[x-1][y] != 'T') {
            new_t = min(t, depth[x-1][y] - cost);
            if(new_t >= 0) pq.push({{new_t, visited + 1}, {x-1, y}});
        }
        if(y && grid[x][y-1] != 'T') {
            new_t = min(t, depth[x][y-1] - cost);
            if(new_t >= 0) pq.push({{new_t, visited + 1}, {x, y-1}});
        }
        if(x+1<n && grid[x+1][y] != 'T') {
            new_t = min(t, depth[x+1][y] - cost);
            if(new_t >= 0) pq.push({{new_t, visited + 1}, {x+1, y}});
        }
        if(y+1<n && grid[x][y+1] != 'T') {
            new_t = min(t, depth[x][y+1] - cost);
            if(new_t >= 0) pq.push({{new_t, visited + 1}, {x, y+1}});
        }
    }
    cout << -1 << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int t=1;
    while(t--) solve();

    return 0;
}

• Subtask 1: 2 / 100