Submission #897129

#	Time	Username	Problem	Language	Result	Execution time	Memory
897129		LCJLY	Swapping Cities (APIO20_swap)	C++14	36 / 100	657 ms	131660 KiB

swap

#include "swap.h"

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int>pii;
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << "  " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << "  " << j << " " << #i << "  " << q << " " << #p << endl; 
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
#define int long long

vector<int>adj[500005];
long long cost[500005];

struct DSU{
	vector<int>e;
	void init(int n){
		e=vector<int>(n,-1);
	}
	
	int get(int x){return e[x]<0?x:e[x]=get(e[x]);}
	
	bool unite(int x, int y){ //x is par
		x=get(x),y=get(y);
		if(x==y) return 0;
		adj[x].push_back(y);
		adj[y].push_back(x);
		e[x]+=e[y];
		e[y]=x;
		return 1;
	}
};

int two[22][500005];
int d[500005];
void dfs(int index, int par){
	for(int x=0;x<20;x++){
		if(two[x][index]==-1) break;
		two[x+1][index]=two[x][two[x][index]];
	}
	
	for(auto it:adj[index]){
		if(it==par) continue;
		two[0][it]=index;
		d[it]=d[index]+1;
		dfs(it,index);
	}
}

int lca(int a, int b){
	if(d[a]>d[b]) swap(a,b);
	int diff=d[b]-d[a];
	for(int x=0;x<20;x++){
		if(diff&(1<<x)) b=two[x][b];
	}
	
	if(a==b) return a;
	for(int x=19;x>=0;x--){
		if(two[x][b]!=two[x][a]){
			a=two[x][a];
			b=two[x][b];
		}
	}
	return two[0][a];
}

bool done[300005];


int root=0;
void init(int32_t n, int32_t m, vector<int32_t> u, vector<int32_t> v, vector<int32_t> w){
	pair<int,pii>edge[m];
	for(int x=0;x<m;x++){
		edge[x].first=w[x];
		edge[x].second={u[x],v[x]};
	}
	
	sort(edge,edge+m);
	
	DSU dsu;
	dsu.init(n+m+20);
	
	int in[n+5];
	memset(in,0,sizeof(in));
	
	root=n+1;
	
	for(int x=0;x<m;x++){
		int l=edge[x].second.first;
		int r=edge[x].second.second;
		int hold=edge[x].first;
		in[l]++;
		in[r]++;
	
		l=dsu.get(l);
		r=dsu.get(r);
		if(l==r){
			done[l]=true;
			cost[l]=hold;
		}
		else{				
			if(done[l]||done[r]) done[root]=true;
			if(in[edge[x].second.first]>2||in[edge[x].second.second]>2) done[root]=true;
			dsu.unite(root,l);
			dsu.unite(root,r);
			cost[root]=hold;
			root++;
		}
	}
	root--;
	memset(two,-1,sizeof(two));
	
	dfs(root,-1);
}

int32_t getMinimumFuelCapacity(int32_t x, int32_t y){
	int hold=lca(x,y);
	
	if(done[hold]){
		return cost[hold];
	}
	
	int cur=hold;
	for(int bit=19;bit>=0;bit--){
		if(d[cur]>=(1<<bit)){
			if(!done[two[bit][cur]]){
				cur=two[bit][cur];
			}
		}
	}
	if(cur==root) return -1;
	return cost[two[0][cur]];
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 23 / 23
• Subtask 6: 0 / 27