Submission #500975

#	Time	Username	Problem	Language	Result	Execution time	Memory
500975		AmirElarbi	Furniture (JOI20_furniture)	C++14	0 / 100	10 ms	4428 KiB

furniture

#include <bits/stdc++.h>
#define vi vector<int>
#define ve vector
#define ll long long
#define vf vector<float>
#define vll vector<pair<ll,ll>>
#define ii pair<int,int>
#define vvi vector<vi>
#define vii vector<ii>
#define gii greater<ii>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define INF 1e9
#define eps 1e-7
#define eps1 1e-25
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MAX_A 1e5+5
#define V 450
using namespace std;
const int MOD = 1e9+7;
const int nax = 1000005;
short grid[1005][1005],vis[1005][1005];
int cnt[nax];
int n,m;
int mov[4][2] = {{0,1},{1,0},{-1,0},{0,-1}};
int dfs(int x, int y){
    if(x == n && y == m) return 0;
    if(x > n || y > m) return 1;
    if(grid[x][y]==1) return 1;
    if(vis[x][y]) return grid[x][y];
    vis[x][y] = 1;
    grid[x][y] = min(dfs(x+1,y),dfs(x,y+1));
    cnt[x+y]+=(grid[x][y]==0);
    return grid[x][y];
}
void upd(int x, int y){
    for (int i = 0; i < 4; ++i)
    {
        int nx = x + mov[i][0], ny = y + mov[i][1];
        if(nx < 1 || ny < 1 || nx >n || ny > m ||grid[nx][ny] == 1||(nx == 1 && ny == 1)||(nx == n && ny == m)) continue;
        if(grid[nx-1][ny]&& grid[nx][ny-1]){
            grid[nx][ny] = 1;
        }
        if(grid[nx+1][ny] && grid[nx][ny+1]){
            grid[nx][ny] = 1;
        }
        if(grid[nx][ny]){
            cnt[nx+ny]--;
            upd(nx,ny);
        }
    }
}
int main(){
    optimise;
    cin>>n >>m;
    for (int i = 0; i < nax; ++i)
    {
        for (int j = 0; j < nax; ++j)
        {
            grid[i][j] = 1;
        }
    }
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            cin >> grid[i][j];
            if(grid[i][j] == 0) grid[i][j] = 2;
        }
    }
    dfs(1,1);
    grid[n][m] = 0;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            if(grid[i][j]==2) 
                grid[i][j] = 1;
        }
    }
    int q;
    cin >>q;
    while(q--){
        int x,y;
        cin >> x >> y;
        if(grid[x][y] == 1){
            cout << 1 << endl;
            continue;
        }
        else if(cnt[x+y] <= 1){
            cout << 0 << endl;
            continue;
        }
        cout << 1 << endl;
        grid[x][y] = 1;
        cnt[x+y]--;
        upd(x,y);
    }
}

Compilation message (stderr)

furniture.cpp: In function 'int main()':
furniture.cpp:62:24: warning: iteration 1005 invokes undefined behavior [-Waggressive-loop-optimizations]
   62 |             grid[i][j] = 1;
      |             ~~~~~~~~~~~^~~
furniture.cpp:60:27: note: within this loop
   60 |         for (int j = 0; j < nax; ++j)
      |                         ~~^~~~~
furniture.cpp:62:24: warning: iteration 1005 invokes undefined behavior [-Waggressive-loop-optimizations]
   62 |             grid[i][j] = 1;
      |             ~~~~~~~~~~~^~~
furniture.cpp:58:23: note: within this loop
   58 |     for (int i = 0; i < nax; ++i)
      |                     ~~^~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 95