Submission #530618

#	Time	Username	Problem	Language	Result	Execution time	Memory
530618		kevin	Dango Maker (JOI18_dango_maker)	C++17	13 / 100	124 ms	211984 KiB

dango_maker

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define nl cout<<"\n"
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define ca(v) for(auto i:v) cout<<i<<" ";

const int MOD = 1e9 + 7;

int onv[3001][3001];
int onh[3001][3001];
list<int> adj[3001*3001];
bool vis[3001*3001];

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (fopen("input.in", "r")) freopen("input.in", "r", stdin);
    int n, m; cin>>n>>m;
    char grid[n][m];
    for(int i=0; i<n; i++){
        for(int j=0; j<m; j++){
            cin>>grid[i][j];
        }
    }
    int cnt = 0;
    for(int i=0; i<n; i++){
        for(int j=0; j<m; j++){
            if(grid[i][j] == 'R' && j+2 < m && grid[i][j+1] == 'G' && grid[i][j+2] == 'W') onh[i][j] = ++cnt;
        }
    }
    for(int j=0; j<m; j++){
        for(int i=0; i<n; i++){
            if(grid[i][j] == 'R' && i+2 < n && grid[i+1][j] == 'G' && grid[i+2][j] == 'W') onv[i][j] = ++cnt;
        }
    }
    for(int i=0; i<n; i++){
        for(int j=0; j<m; j++){
            if(onh[i][j]){
                for(int k=0; k<3; k++){
                    if(i-k >= 0 && j+k < m && onv[i-k][j+k]){
                        adj[onh[i][j]].push_back(onv[i-k][j+k]);
                        adj[onv[i-k][j+k]].push_back(onh[i][j]);
                    }
                }
            }
        }
    }
    int ans = 0;
    vector<int> label(cnt+1, 0);
    for(int i=1; i<=cnt; i++){
        if(!vis[i]){
            vis[i] = 1;
            int cn[2] = {0, 0};
            queue<pair<int, int>> q;
            q.push({i, 0});
            while(q.size()){
                auto c = q.front();
                cn[c.s]++;
                q.pop();
                for(int a:adj[c.f]){
                    if(!vis[a]){
                        label[a] = 1-c.s;
                        q.push({a, 1-c.s});
                        vis[a] = 1;
                    }
                    else assert(label[a] == 1-c.s);
                }
            }
            ans += max(cn[0], cn[1]);
        }
    }
    cout<<ans;
}

Compilation message (stderr)

dango_maker.cpp: In function 'int main()':
dango_maker.cpp:21:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     if (fopen("input.in", "r")) freopen("input.in", "r", stdin);
      |                                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 0 / 20
• Subtask 3: 0 / 67