Submission #530624

#	Time	Username	Problem	Language	Result	Execution time	Memory
530624		kevin	Dango Maker (JOI18_dango_maker)	C++17	0 / 100	4 ms	7372 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[300001];
bool vis[3000001];
int dp[3000001][2];

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;
    for(int a=0; a<n; a++){
        for(int b=m-1; b>=0; b--){
            int i = max(onh[a][b], onv[a][b]);
            if(i){
                vis[i] = 1;
                queue<int> q;
                q.push(i);
                while(q.size()){
                    int c = q.front();
                    q.pop();
                    dp[c][0] = 1;
                    for(int a:adj[c]){
                        if(!vis[a]){
                            q.push(a);
                            vis[a] = 1;
                        }
                        else{
                            dp[a][0] += dp[c][1];
                            dp[a][1] += max(dp[c][1], dp[c][0]);
                        }
                    }
                    if(q.size() == 0){
                        ans += max(dp[c][0], dp[c][1]);
                    }
                }
            }
        }
    }
    cout<<ans;
}

Compilation message (stderr)

dango_maker.cpp: In function 'int main()':
dango_maker.cpp:22:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |     if (fopen("input.in", "r")) freopen("input.in", "r", stdin);
      |                                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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