Submission #960481

#	Time	Username	Problem	Language	Result	Execution time	Memory
960481		LmaoLmao	Mecho (IOI09_mecho)	C++17	0 / 100	3 ms	600 KiB

mecho

#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
 
using ll = long long;
using ii = pair<int, int>;
 
const int N = 1e6+5;
const int INF = 1e9;

int d[1000][1000],m[1000][1000],n,s;
char a[1000][1000];
int dx[4]={1,0,0,-1};
int dy[4]={0,1,-1,0};
ii pos,h;

bool bfs(int x) {
    queue<ii> q;
    q.push(pos);
    for(int i=0;i<n;i++) {
        for(int j=0;j<n;j++) {
            m[i][j]=0;
        }
    }
    while(!q.empty()) {
        ii u=q.front();
        q.pop();
        for(int i=0;i<4;i++) {
            ii v={u.fi+dx[i],u.se+dy[i]};
            if(v.fi<0 || v.fi>=n || v.se<0 || v.se>=n) continue;
            if(m[v.fi][v.se]==0 && a[v.fi][v.se]!='T' && d[v.fi][v.se]-x>=(m[u.fi][u.se]+1)/s && a[v.fi][v.se]!='M') {
                m[v.fi][v.se]=m[u.fi][u.se]+1;
                q.push(v);
            }
        }
    }
    if(m[h.fi][h.se]>0) return 1; else return 0;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    queue<ii> q;
    cin >> n >> s;
    for(int i=0;i<n;i++) {
        for(int j=0;j<n;j++) {
            cin >> a[i][j];
            if(a[i][j]=='H') {
                q.push({i,j});
            }
            if(a[i][j]=='M') pos={i,j};
            if(a[i][j]=='D') h={i,j};
        }
    }
    while(!q.empty()) {
        ii u=q.front();
        q.pop();
        for(int i=0;i<4;i++) {
            ii v={u.fi+dx[i],u.se+dy[i]};
            if(v.fi<0 || v.fi>=n || v.se<0 || v.se>=n) continue;
            if(d[v.fi][v.se]==0 && a[v.fi][v.se]!='T' && a[v.fi][v.se]!='H') {
                d[v.fi][v.se]=d[u.fi][u.se]+1;
                q.push(v);
            }
        }
    }
    int l=0,r=100,ans=-1;
    while(l<=r) {
        int m=(l+r)/2;
        if(bfs(m)) {
            ans=m;
            l=m+1;
        }
        else {
            r=m-1;
        }
    }
    cout << -1;
    return 0;
}

Compilation message (stderr)

mecho.cpp: In function 'int main()':
mecho.cpp:73:19: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
   73 |     int l=0,r=100,ans=-1;
      |                   ^~~
mecho.cpp:46:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     freopen("in.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
mecho.cpp:47:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     freopen("out.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100