BZOJ 1924 所驼门王的宝藏（强连通分量+树形DP）

int n,r,c;
map<i64,int> mp;
map<int,int> mp1,mp2;


struct node
{
    int x,y,op;
};


node a[N];
int visit[N];
vector<int> V1[N],V2[N];
int X,Y;


void Add(int x,int y,int i)
{
    if(mp1.count(x)==0) mp1[x]=++X;
    V1[mp1[x]].pb(i);
    
    if(mp2.count(y)==0) mp2[y]=++Y;
    V2[mp2[y]].pb(i);
}


int dx[]={-1,-1,-1,0,1,1,1,0};
int dy[]={-1,0,1,1,1,0,-1,-1};


vector<int> g[N];




void build()
{
    int i,j,k,p,x,y;
    i64 q;
    FOR1(i,n)
    {
        if(a[i].op==1)
        {
            p=mp1[a[i].x];
            FOR0(j,SZ(V1[p])) if(V1[p][j]!=i) g[i].pb(V1[p][j]); 
        }
        else if(a[i].op==2)
        {
            p=mp2[a[i].y];
            FOR0(j,SZ(V2[p])) if(V2[p][j]!=i) g[i].pb(V2[p][j]);
        }
        else
        {
            FOR0(j,8)
            {
                x=a[i].x+dx[j];
                y=a[i].y+dy[j];
                if(x<1||x>r||y<1||y>c) continue;
                q=x*M+y;
                if(mp.count(q)) g[i].pb(mp[q]);
            }
        }
    }
}


int dfn[N],low[N],color[N],id,num,size[N];
stack<int> St;


void DFS(int u)
{
    dfn[u]=low[u]=++id;
    St.push(u);
    
    int i,v;
    FOR0(i,SZ(g[u]))
    {
        v=g[u][i];
        if(!dfn[v]) DFS(v),upMin(low[u],low[v]);
        else if(!visit[v]) upMin(low[u],dfn[v]);
    }
    if(low[u]==dfn[u])
    {
        num++;
        do
        {
            v=St.top();
            St.pop();
            visit[v]=1;
            color[v]=num;
            size[num]++;
        }while(u!=v);
    }
}




vector<int> G[N];
int d[N];


int rebuild()
{
    int i,j;
    FOR1(i,n) FOR0(j,SZ(g[i]))
    {
        if(color[i]!=color[g[i][j]])
        {
            G[color[i]].pb(color[g[i][j]]);
            d[color[g[i][j]]]++;
        }
    } 
}


int f[N];


int dfs(int u)
{
    if(f[u]!=-1) return f[u];
    f[u]=0;
    int i,v;
    FOR0(i,SZ(G[u])) upMax(f[u],dfs(G[u][i]));
    f[u]+=size[u];
    return f[u];
}


int main()
{
    RD(n,r,c);
    int i;
    i64 p;
    FOR1(i,n)
    {
        RD(a[i].x,a[i].y,a[i].op);
        Add(a[i].x,a[i].y,i);
        p=a[i].x*M+a[i].y;
        mp[p]=i;
    }
    build();
    FOR1(i,n) if(!visit[i]) DFS(i);
    rebuild();clr(f,-1);
    int ans=0;
    FOR1(i,num) if(!d[i]) upMax(ans,dfs(i));
    PR(ans);
}