Submission #1084583

#	Time	Username	Problem	Language	Result	Execution time	Memory
1084583		kiethm07	Mecho (IOI09_mecho)	C++11	36 / 100	806 ms	11604 KiB

mecho

#include <bits/stdc++.h>

#define pii pair<int,int>
#define iii pair<int,pii>
#define fi first
#define se second

#define vi vector<int>
#define vii vector<pii>
#define pb(i) push_back(i)
#define all(x) x.begin(),x.end()

#define TEXT "a"

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const int inf = 1e9 + 7;
const ld eps = 1e-8;
const double pi = acos(-1);
const int N = 805;

int n,s;
int f[N][N], g[N][N];
char a[N][N];
int dx[4] = {0,0,1,-1};
int dy[4] = {1,-1,0,0};

bool check(int val){
    queue<pii> q;
    memset(f,-1,sizeof(f));
    memset(g,-1,sizeof(g));
    pii M, D;
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= n; j++){
            if (a[i][j] == 'M') M = pii(i,j);
            if (a[i][j] == 'D') D = pii(i,j);
            if (a[i][j] == 'H'){
                q.push(pii(i,j));
                f[i][j] = 0;
            }
        }
    }
    while(!q.empty()){
        pii u = q.front();
        q.pop();
        if (f[u.fi][u.se] >= val) continue;
        for (int i = 0; i < 4; i++){
            int x = u.fi + dx[i];
            int y = u.se + dy[i];
            if (x == 0 || x > n || y == 0 || y > n) continue;
            if (a[x][y] == 'T' || a[x][y] == 'D') continue;
            if (f[x][y] != -1) continue;
            f[x][y] = f[u.fi][u.se] + 1;
            q.push(pii(x,y));
        }
    }
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= n; j++){
            if (f[i][j] == -1) continue;
            f[i][j] = 0;
            q.push(pii(i,j));
        }
    }
    while(!q.empty()){
        pii u = q.front();
        q.pop();
        for (int i = 0; i < 4; i++){
            int x = u.fi + dx[i];
            int y = u.se + dy[i];
            if (x == 0 || x > n || y == 0 || y > n) continue;
            if (a[x][y] == 'T' || a[x][y] == 'D') continue;
            if (f[x][y] != -1) continue;
            f[x][y] = f[u.fi][u.se] + s;
            q.push(pii(x,y));
        }
    }
    f[D.fi][D.se] = inf;
    g[M.fi][M.se] = 0;
    q.push(M);
    while(!q.empty()){
        pii u = q.front();
        q.pop();
        for (int i = 0; i < 4; i++){
            int x = u.fi + dx[i];
            int y = u.se + dy[i];
            if (x == 0 || x > n || y == 0 || y > n) continue;
            if (a[x][y] == 'T') continue;
            if (g[x][y] != -1) continue;
            if (f[x][y] < g[u.fi][u.se]) continue;
            g[x][y] = g[u.fi][u.se] + 1;
            q.push(pii(x,y));
        }
    }
    return g[D.fi][D.se] != -1;
}

int main(){
    cin.tie(0) -> sync_with_stdio(0);
    if (fopen(TEXT".inp","r")){
        freopen(TEXT".inp","r",stdin);
        freopen(TEXT".out","w",stdout);
    }
    cin >> n >> s;
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= n; j++) cin >> a[i][j];
    }
    int res = -1;
    int l = 0;
    int r = inf;
//    cout << check(1) << "\n";
//    for (int i = 1; i <= n; i++){
//        for (int j = 1; j <= n; j++){
//            cout << g[i][j] << "   ";
//        }
//        cout << "\n";
//    }
    while(l <= r){
        int mid = (l + r) / 2;
        if (check(mid)){
            res = mid;
            l = mid + 1;
        }
        else r = mid - 1;
    }
    cout << res << "\n";
    return 0;
}

Compilation message (stderr)

mecho.cpp: In function 'int main()':
mecho.cpp:104:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |         freopen(TEXT".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
mecho.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(TEXT".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 36 / 100