Submission #965883

#	Time	Username	Problem	Language	Result	Execution time	Memory
965883		owoovo	Swapping Cities (APIO20_swap)	C++17	100 / 100	189 ms	39256 KiB

swap

#include "swap.h"
#include<bits/stdc++.h>
#define ll long long 
#define F first 
#define S second 
using namespace std;
const int maxn=1e9+10;
int deg[100010],tag[100010],wh[100010],dep[100010],jpt[100010][20],jpw[100010][20];
vector<int> e[100010];
struct Dsu{
    int ori[100010]={},si[100010]={};
    void init(int n){
        for(int i=0;i<n;i++)ori[i]=i,si[i]=1;
        return ;
    }
    int f(int a){
        return a==ori[a]?a:f(ori[a]);
    }
    void onion(int a,int b,int w){
        int ok=0;
        if(deg[a]>=3||deg[b]>=3)ok=1;
        a=f(a),b=f(b);
        if(a==b){
            wh[a]=min(wh[a],w);
            return ;
        }
        if(si[a]>si[b])swap(a,b);
        si[b]+=si[a];
        ori[a]=b;
        jpt[a][0]=b;
        jpw[a][0]=w;
        if(ok)wh[b]=min(wh[b],w);
        e[a].push_back(b),e[b].push_back(a);
        return;
    }
}dsu;
void dfs(int now,int last){
    dep[now]=dep[last]+1;
    for(auto x:e[now]){
        if(x==last)continue;
        dfs(x,now);
        wh[now]=min(wh[now],max(wh[x],jpw[x][0]));
    }
    return;
}
void dfs2(int now,int last,int w){
    w=min(w,wh[now]);
    wh[now]=min(wh[now],w);
    for(auto x:e[now]){
        if(x==last)continue;
        dfs2(x,now,max(w,jpw[x][0]));
    }
    return ;
}
void init(int n, int m,vector<int> u, vector<int> v, vector<int> w) {
    for(int i=0;i<n;i++)wh[i]=maxn;
    dsu.init(n);
    vector<pair<int,pair<int,int>>>edge;
    for(int i=0;i<m;i++)edge.push_back({w[i],{u[i],v[i]}});
    sort(edge.begin(),edge.end());
    for(auto [x,y]:edge){
        auto [q,r]=y;
        deg[q]++;
        deg[r]++;
        dsu.onion(q,r,x);
    }
    for(int i=1;i<=18;i++){
        for(int j=0;j<n;j++){
            jpt[j][i]=jpt[jpt[j][i-1]][i-1];
            jpw[j][i]=max(jpw[j][i-1],jpw[jpt[j][i-1]][i-1]);
        }
    }
    for(int i=0;i<n;i++)if(i==dsu.ori[i])dfs(i,i),dfs2(i,i,maxn);
}
int lca(int u,int v){
    if(dep[u]<dep[v])swap(u,v);
    int ans=0;
    for(int i=18;i>=0;i--){
        if(dep[u]-(1<<i)>=dep[v]){
            //cout<<jpw[u][i]<<" "<<u<<" k\n";
            ans=max(ans,jpw[u][i]);
            u=jpt[u][i];
        }
    }
    if(u==v){
        //cout<<ans<<" "<<wh[u]<<"\n";

        return max(ans,wh[u]);
    }
    for(int i=18;i>=0;i--){
        if(jpt[u][i]!=jpt[v][i]){
            ans=max(ans,jpw[u][i]);
            ans=max(ans,jpw[v][i]);
            u=jpt[u][i];
            v=jpt[v][i];
        }
    }
    ans=max(ans,jpw[u][0]);
    ans=max(ans,jpw[v][0]);
    u=jpt[u][0];
    //cout<<ans<<" "<<wh[u]<<"\n";
    return max(ans,wh[u]);
}
int getMinimumFuelCapacity(int u, int v) {
    int ans=lca(u,v);
    return ans==maxn?-1:ans;
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 23 / 23
• Subtask 6: 27 / 27