Submission #583555

#	Time	Username	Problem	Language	Result	Execution time	Memory
583555		Trent	Mecho (IOI09_mecho)	C++17	23 / 100	217 ms	7056 KiB

mecho

#include "bits/stdc++.h"
#include "ext/pb_ds/assoc_container.hpp"

using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define open(g) string _name_ = g; freopen((_name_ + ".in").c_str(), "r", stdin); freopen((_name_ + ".out").c_str(), "w", stdout)
#define printArr(a, len) for(int asdf = 0; asdf < (len); ++asdf) cout << (a)[asdf] << ' '; cout << '\n';
#define boost() cin.sync_with_stdio(0); cin.tie(0)
#define forR(i, x) for(int i = 0; i < x; ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define all(i) i.begin(), i.end()
#define pii pair<int, int>
#define vi vector<int>
#define si set<int>
#define usi unordered_set<int>
#define mii map<int, int>
#define umii unordered_map<int, int>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")

const int MN = 810, INF = 1e9 + 10;
struct coord{int r, c;};
struct bear{int r, c, sl;};
bool vis[MN][MN];
int bee[MN][MN], ber[MN][MN]; // minimum # of minutes needed to end here
char grid[MN][MN];
int dir[4][2] = {{1, 0}, {0, 1}, {0, -1}, {-1, 0}};
int n, s;
int mr, mc;

bool ib(int r, int c){return 0 <= r && r < n && 0 <= c && c < n;}
bool iv(int r, int c){return ib(r, c) && grid[r][c] != 'T';}

// t = number of minutes bear eats
bool pos(int t){
    if(bee[mr][mc] <= t) return false;
    deque<bear> bfs = {{mr, mc, 0}};
    forR(a, MN) forR(b, MN) vis[a][b] = false;
    forR(a, MN) forR(b, MN) ber[a][b] = 0;
    ber[mr][mc] = t;
    vis[mr][mc] = true;
    while(!bfs.empty()){
        auto [r, c, sl] = bfs.front();
        bfs.pop_front();
        if(!(sl > 0 || ber[r][c] < bee[r][c])){
            cout << r << ' ' << c << ' ' << sl << '\n';
            cout << "bad";
        }
        if(grid[r][c] == 'D') {
            return true;
        }
        for(auto [rc, cc] : dir){
            auto [nr, nc] = pii{r+rc, c+cc};
            int dis = ber[r][c] + (sl == 0);
            int nsl = sl == 0 ? s - 1 : sl - 1;
            // cout << r << ' ' << c << ' ' << sl << ' ' << nr << ' ' << nc << ' ' << dis << ' ' << bee[nr][nc] << '\n';
            if(iv(nr, nc) && grid[nr][nc] != 'H' && !vis[nr][nc] && (nsl != 0 || dis < bee[nr][nc])){
                ber[nr][nc] = dis;
                vis[nr][nc] = true;
                bfs.push_back({nr, nc, nsl});
            }
        }
    }
    return false;
}

signed main() {
    cin >> n >> s;
    deque<coord> bfs;
    forR(r, n) forR(c, n){
        cin >> grid[r][c];
        if(grid[r][c] == 'H') {
            bfs.push_back({r, c});
            vis[r][c] = true;
        } else if(grid[r][c] == 'M'){
            mr=r, mc=c;
        }
    }
    while(!bfs.empty()){
        auto [r, c] = bfs.front();
        bfs.pop_front();
        for(auto [cr, cc] : dir){
            auto [nr, nc] = pii {r + cr, c + cc};
            if(iv(nr, nc) && grid[nr][nc] != 'D' && !vis[nr][nc]){
                vis[nr][nc] = true;
                bee[nr][nc] = bee[r][c] + 1;
                bfs.push_back({nr, nc});
            }
        }
    }
    forR(r, MN) forR(c, MN) if(!vis[r][c]) bee[r][c] = INF;
    if(!pos(0)) cout << "-1\n";
    else {
        // TODO fix hi
        int lo=0, hi=MN * MN;
        while(hi - lo > 1){
            int mid = (lo + hi) / 2;
            if(pos(mid)) lo = mid;
            else hi = mid;
        }
        cout << lo << '\n';
    }
}

• Subtask 1: 23 / 100