Submission #1003913

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003913		vjudge1	Paint (COI20_paint)	C++17	48 / 100	1317 ms	524288 KiB

paint

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

#define N 200010
#define M 50
#define INFLL 2000000000000000020
#define pb push_back

typedef long long ll;
typedef pair<ll,ll> pll;

ll h;
ll n,m;
ll head[N];
ll color[N];
bool marc[N];
unordered_set<ll>reach[N];
vector<ll>merges;

ll transform(ll i,ll j)
{
    return i*m+j-m;
}

ll Dx[10]={-1,0,1,0};
ll Dy[10]={0,1,0,-1};

bool valid(ll i,ll j)
{
    return (bool)(i>0 && i<=n && j>0 && j<=m);
}

void DFS(ll i,ll j)
{
    ll x=transform(i,j),k,ni,nj,y;
    marc[x]=true;
    head[x]=h;
    for(k=0;k<4;k++)
    {
        ni=i+Dx[k];
        nj=j+Dy[k];
        y=transform(ni,nj);
        if(!valid(ni,nj))
            continue;
        if(color[y]==color[x])
        {
            if(!marc[y])
                DFS(ni,nj);
        }else
            reach[h].insert(y);
    }
    return;
}

ll Find(ll u)
{
    if(head[u]==u)
        return u;
    return head[u]=Find(head[u]);
}

void merge(ll u,ll v)
{
    head[v]=u;
    for(auto x : reach[v])
    {
        if(Find(x)==u)
            continue;
        reach[u].insert(x);
    }
    reach[u].erase(v);
    return;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    ll q,x,i,j,c,u,v;

    cin >> n >> m;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            x=transform(i,j);
            cin >> color[x];
        }
    }
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            x=transform(i,j);
            if(marc[x])
                continue;
            h=x;
            DFS(i,j);
        }
    }
    cin >> q;
    while(q)
    {
        q--;
        cin >> i >> j >> c;
        x=transform(i,j);
        u=Find(x);
        color[u]=c;
        for(auto r : reach[u])
        {
            v=Find(r);
            if(u==v)
                continue;
            if(color[v]==c)
            {
                merges.pb(v);
            }
        }
        while(!merges.empty())
        {
            merge(u,merges.back());
            merges.pop_back();
        }
    }
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            x=transform(i,j);
            u=Find(x);
            cout << color[u] << ((j==m) ? '\n' : ' ');
        }
    }

    return 0;
}

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