Submission #1241995

#	Time	Username	Problem	Language	Result	Execution time	Memory
1241995		NeilP	Mecho (IOI09_mecho)	C++20	30 / 100	1094 ms	17068 KiB

mecho

#include <iostream>
#include <queue>
#include <tuple>
using namespace std;

int n, s;
char grid[800][800];
int distb[800][800];
bool vis[800][800];
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
int homex, homey;
int honx, hony;

bool inside1(pair<int, int> p){
    return p.first >= 0 && p.first < n && p.second >= 0 && p.second < n;
}

bool inside2(pair<int, int> p){
    return p.first >= 0 && p.first < n && p.second >= 0 && p.second < n && grid[p.first][p.second] != 'H'
    && grid[p.first][p.second] != 'T';
}

int main()
{
    queue<pair<int, int>> q;
    cin >> n >> s;
    for(int i = 0; i < n; i++){
        string line;
        cin >> line;
        for(int j = 0; j < n; j++){
            grid[i][j] = line[j];
            distb[i][j] = 2*n;
            if(grid[i][j] == 'H'){
                q.push({i, j});
                distb[i][j] = 0;
            }
            if(grid[i][j] == 'D'){
                homex = i;
                homey = j;
            }
            if(grid[i][j] == 'M'){
                honx = i;
                hony = j;
            }
        }
    }
    
    while(!q.empty()){
        auto x = q.front();
        q.pop();
        for(int i = 0; i < 4; i++){
            pair<int, int> y = {x.first + dx[i], x.second + dy[i]};
            if(inside1(y) && distb[x.first][x.second] + 1 < distb[y.first][y.second]){
                distb[y.first][y.second] = distb[x.first][x.second] + 1;
                q.push({y.first, y.second});
            }
        }
    }
    
    vis[homex][homey] = true;
    queue<tuple<int, int, int>> deq; // x, y, moves
    queue<tuple<int, int, int>> deq1; // x, y, moves
    deq.push({homex, homey, 0});
    int mins = distb[homex][homey] - 1;
    bool stop = false;
    while(mins >= 0){
        while(!deq.empty()){
            auto t = deq.front();
            if(get<0>(t) == honx && get<1>(t) == hony){
                stop = true;
                break;
            }
            deq1.push({get<0>(t), get<1>(t), 0});
            deq.pop();
            if(get<2>(t) < s){
                for(int i = 0; i < 4; i++){
                    pair<int, int> y = {get<0>(t) + dx[i], get<1>(t) + dy[i]};
                    if(inside2(y) && !vis[y.first][y.second] && distb[y.first][y.second] > mins){
                        vis[y.first][y.second] = true;
                        deq.push({y.first, y.second, get<2>(t) + 1});
                    }
                }
            }
        }
        if(stop) break;
        deq = deq1;
        deq1 = queue<tuple<int, int, int>>();
        mins --;
    }
    cout << mins << endl;
}

• Subtask 1: 30 / 100