제출 #1008468

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1008468		ByeWorld	Mecho (IOI09_mecho)	C++14	100 / 100	215 ms	14940 KiB

mecho

#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
#define ll long long
#define int long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<pii, int> ipii;
const int MAXN = 1010;
const int MAXA = 2e3+10;
const int INF = 1e18+10;
const int LOG = 63;
const int MOD = 1e9+7;
const int SQRT = 450;
const vector<int> NOL = {};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const vector<int> dx = {1, -1, 0, 0};
const vector<int> dy = {0, 0, 1, -1};

int n, m, k;
char c[MAXN][MAXN];
int dis[MAXN][MAXN], val[MAXN][MAXN];
int sta, en;

bool valid(int x, int y){
    if(x<1 || x>n || y<1 || y>m) return 0;
    if(c[x][y] == 'T') return 0;
    return 1;
}

queue <pii> q;
void bfs(){
    while(!q.empty()){
        int dist = q.front().fi, x = q.front().se/MAXN, y = q.front().se%MAXN;
        q.pop();
        if(dist > dis[x][y]) continue;
        for(int i=0; i<4; i++){
            int nx = x+dx[i], ny = y+dy[i];
            if(!valid(nx, ny)) continue;
            if(c[nx][ny] == 'D') continue;
            if(dis[nx][ny] <= dis[x][y]+k) continue;
            dis[nx][ny] = dis[x][y]+k;
            q.push({dis[nx][ny], nx*MAXN+ny});
        }
    }
}
bool bisa(int num){
    if(dis[sta/MAXN][sta%MAXN] <= num) return 0;
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++) val[i][j] = INF;
    q.push({num, sta}); val[sta/MAXN][sta%MAXN] = num;
    while(!q.empty()){
        int dist = q.front().fi, x = q.front().se/MAXN, y = q.front().se%MAXN;
        q.pop();
        if(dist >= dis[x][y]) continue; // bee ke sini
        if(dist > val[x][y]) continue;
        for(int i=0; i<4; i++){
            int nx = x+dx[i], ny = y+dy[i];
            if(!valid(nx, ny)) continue;
            if(val[nx][ny] <= val[x][y]+1) continue;
            if(dis[nx][ny] <= val[x][y]+1) continue;
            val[nx][ny] = val[x][y]+1;
            q.push({val[nx][ny], nx*MAXN+ny});
        }
    }
    return (val[en/MAXN][en%MAXN] < INF);
}
signed main(){
    // ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin >> n >> k; m = n;
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++) dis[i][j] = INF;
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            cin >> c[i][j];
            if(c[i][j]=='H'){
                q.push({0, i*MAXN+j});
                dis[i][j] = 0;
            } else if(c[i][j]=='D') en = i*MAXN+j;
            else if(c[i][j]=='M') sta = i*MAXN+j;
        }
    }
    bfs();
    // for(int i=1; i<=n; i++){
    //     for(int j=1; j<=m; j++) cout << dis[i][j] << " \n"[j==m];
    // }
    int l=0, r=INF, mid=0, cnt=-1;
    while(l<=r){
        mid = md;
        if(bisa(mid)){ cnt = mid; l = mid+1;}
        else r = mid-1;
    }
    cout << (cnt==-1 ? -1 : cnt/k) << '\n';
}

• Subtask 1: 100 / 100