Submission #908660

#	Time	Username	Problem	Language	Result	Execution time	Memory
908660		lighton	Paint (COI20_paint)	C++17	8 / 100	3080 ms	33752 KiB

paint

#include<bits/stdc++.h>
#define forf(i,a,b) for(int i = a; i<=b; i++)
#define all(v) v.begin(),v.end()
typedef long long ll;
using namespace std;
int R,S,N,Q;
vector<vector<int> > num, col;
struct DSU{
    int grp[200011];
    int col[200011];
    vector<int> comp[200011];
    vector<int> adj[200011];
    void init(){
        forf(i,1,N){
            grp[i] = i;
            comp[i].push_back(i);
        }
    }
    int f(int x){
        if(grp[x] == x) return x;
        return grp[x] = f(grp[x]);
    }
    void u(int x, int y){
        x = f(x); y=f(y);
        if(adj[x].size() > adj[y].size()) swap(x,y);
        for(int &i : adj[x]) adj[y].push_back(i);
        adj[x].clear();
        grp[x] = y;
    }
    void merg(int x){
        vector<int> q;
        for(int i : adj[x]){
            if(f(i) == f(x)) continue;
            if(col[f(i)] == col[f(x)]) q.push_back(i);
        }
        for(int i : q){
            if(f(i)!=f(x)) u(x,i);
        }
    }
} dsu;

void setdsu(){
    forf(i,1,R){
        forf(j,1,S){
            dsu.col[num[i][j]] = col[i][j];
        }
    }
    forf(i,1,R-1){
        forf(j,1,S){
            dsu.adj[num[i][j]].push_back(num[i+1][j]);
            dsu.adj[num[i+1][j]].push_back(num[i][j]);
        }
    }
    forf(i,1,R){
        forf(j,1,S-1){
            dsu.adj[num[i][j+1]].push_back(num[i][j]);
            dsu.adj[num[i][j]].push_back(num[i][j+1]);
        }
    }
}


int main(){
    scanf("%d %d" , &R,&S);
    N=R*S;
    num.resize(R+2); col.resize(R+2);
    forf(i,0,R+1){num[i] = vector<int>(S+2,-1); col[i] = vector<int>(S+2,-1);}
    dsu.init();

    forf(i,1,R){
        forf(j,1,S){
            scanf("%d" , &col[i][j]);
            num[i][j] = S*(i-1)+j;
        }
    }

    setdsu();
    forf(i,1,R){
        forf(j,1,S){
            dsu.merg(num[i][j]);
        }
    }

    scanf("%d" , &Q);
    while(Q--){
        int x,y,c;
        scanf("%d %d %d" , &x,&y,&c);
        dsu.col[dsu.f(num[x][y])]=c;
        dsu.merg(dsu.f(num[x][y]));
    }

    forf(i,1,R) {
        forf(j, 1, S) printf("%d " , dsu.col[dsu.f(num[i][j])]);
        printf("\n");
    }

}

Compilation message (stderr)

paint.cpp: In function 'int main()':
paint.cpp:64:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     scanf("%d %d" , &R,&S);
      |     ~~~~~^~~~~~~~~~~~~~~~~
paint.cpp:72:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |             scanf("%d" , &col[i][j]);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~
paint.cpp:84:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |     scanf("%d" , &Q);
      |     ~~~~~^~~~~~~~~~~
paint.cpp:87:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |         scanf("%d %d %d" , &x,&y,&c);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 0 / 9
• Subtask 3: 0 / 31
• Subtask 4: 0 / 52