Submission #1022341

#	Time	Username	Problem	Language	Result	Execution time	Memory
1022341		imarn	Swapping Cities (APIO20_swap)	C++14	100 / 100	215 ms	66296 KiB

swap

#include<bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
#define ll long long
#define pii pair<ll,ll>
#define pll pair<ll,ll>
#define plx pair<ll,int>
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(),x.end()
#define vi vector<int>
#define vl vector<ll>
#define vvi vector<vi>
using namespace std;
const int mxn=3e5+5;
int pr[mxn];
int up[mxn][20]{0};
int dep[mxn]{0},d[mxn]{0};
vector<int>g[mxn];
int dp[mxn]{0};
bool vis[mxn]{0},ok=0;
int get(int r){
    return pr[r]==r?r:pr[r]=get(pr[r]);
}
void dfs(int u,int p,int l){
    up[u][0]=p;dep[u]=l;
    for(int i=1;i<20;i++)up[u][i]=up[up[u][i-1]][i-1];
    for(auto v:g[u]){
        if(v==p)continue;
        if(!vis[v])vis[v]=1,dp[v]=dp[u];
        dfs(v,u,l+1);
    }
}
int get(int a,int b){
    if(dep[a]>dep[b])swap(a,b);
    for(int i=19;i>=0;i--)if(dep[b]-(1<<i)>=dep[a])b=up[b][i];
    if(a==b)return a;
    for(int i=19;i>=0;i--)if(up[a][i]!=up[b][i])a=up[a][i],b=up[b][i];
    return up[a][0];
}
void init(int N,int M,vi U,vi V,vi W){
    vector<pair<int,pii>>edge;iota(pr,pr+N,0);
    for(int i=0;i<M;i++)edge.pb({W[i],{U[i],V[i]}});
    sort(edge.begin(),edge.end());
    int cr=N-1;
    for(auto it : edge){
        cr++;pr[cr]=cr;dp[cr]=it.f;
        d[it.s.f]++;d[it.s.s]++;
        int x=get(it.s.f),y=get(it.s.s);
        pr[x]=cr;pr[y]=cr;
        if(x==y){g[cr].pb(x);vis[cr]=1;continue;}
        g[cr].pb(x);g[cr].pb(y);
        if(d[it.s.f]>=3||d[it.s.s]>=3||vis[x]||vis[y])vis[cr]=1;
    }if(!vis[cr])return;ok=1;
    dfs(cr,cr,0);
}

int getMinimumFuelCapacity(int X, int Y) {
    if(!ok)return -1;
    return dp[get(X,Y)];
}

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