oj.uz

Submission #224071

# Submission time Handle Problem Language Result Execution time Memory
224071 2020-04-17T07:29:53 Z errorgorn Olympic Bus (JOI20_ho_t4) C++14
0 / 100
 1000 ms 7012 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl;

#define rep(x,start,end) for(auto x=start-(start>end);x!=end-(start>end);x+=(start<end?1:-1))
#define all(x) x.begin(),x.end()

ll MAX(ll a){return a;}
ll MIN(ll a){return a;}
template<typename... Args>
ll MAX(ll a, Args... args) { return max(a,MAX(args...)); }
template<typename... Args>
ll MIN(ll a, Args... args) { return min(a,MIN(args...)); }

#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>

const ll INF=1e18;

struct E{
	int u,v;
	ll len,flip;
	int id;

	E(int a,int b,int c,int d,int e){
		u=a,v=b;
		len=c,flip=d;
		id=e;
	}
};

int n,m;
vector<E> al[205];
vector<E> al_rev[205]; //store reversed edges
vector<E> edges;

priority_queue<ii,vector<ii>,greater<ii> > pq;
ll sf[205]; //source front
ll sb[205]; //source back
ll tf[205]; //sink front
ll tb[205]; //sink back

ll w1[205];
ll w2[205];

bool path[50005]; //is some edge in SP

ll temp,node; //stuff for dijk

void initial_d(){ //epic name
	rep(x,0,205) sf[x]=sb[x]=tf[x]=tb[x]=INF;
	
	sf[1]=0;
	pq.push(ii(sf[1],1));
	while (!pq.empty()){
		temp=pq.top().first;
		node=pq.top().second;
		pq.pop();
		if (temp>sf[node]) continue; //important
		for (auto &it:al[node]){
			if (sf[it.v]>sf[node]+it.len){
				sf[it.v]=sf[node]+it.len;
				pq.push(ii (sf[it.v],it.v));
			}
		}
	} 
	
	sb[1]=0;
	pq.push(ii(sb[1],1));
	while (!pq.empty()){
		temp=pq.top().first;
		node=pq.top().second;
		pq.pop();
		if (temp>sb[node]) continue; //important
		for (auto &it:al_rev[node]){
			if (sb[it.v]>sb[node]+it.len){
				sb[it.v]=sb[node]+it.len;
				pq.push(ii (sb[it.v],it.v));
			}
		}
	} 
	
	tf[n]=0;
	pq.push(ii(tf[n],n));
	while (!pq.empty()){
		temp=pq.top().first;
		node=pq.top().second;
		pq.pop();
		if (temp>tf[node]) continue; //important
		for (auto &it:al[node]){
			if (tf[it.v]>tf[node]+it.len){
				tf[it.v]=tf[node]+it.len;
				pq.push(ii (tf[it.v],it.v));
			}
		}
	} 
	
	tb[n]=0;
	pq.push(ii(tb[n],n));
	while (!pq.empty()){
		temp=pq.top().first;
		node=pq.top().second;
		pq.pop();
		if (temp>tb[node]) continue; //important
		for (auto &it:al_rev[node]){
			if (tb[it.v]>tb[node]+it.len){
				tb[it.v]=tb[node]+it.len;
				pq.push(ii (tb[it.v],it.v));
			}
		}
	}
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin>>n>>m;
	
	int a,b,c,d;
	rep(x,0,m){
		cin>>a>>b>>c>>d;
		
		al[a].push_back(E(a,b,c,d,x));
		al_rev[b].push_back(E(b,a,c,d,x));
		edges.push_back(E(a,b,c,d,x));
	}
	
	initial_d();
	
	/*
	rep(x,1,n+1){
		cout<<sf[x]<<" "<<sb[x]<<" "<<tf[x]<<" "<<tb[x]<<endl;
	}
	*/
	
	//try dijk start and end
	ll ans=sf[n]+tf[1];
	
	//find the path on best line from S->T
	if (sf[n]!=INF){		
		rep(bad,0,m){
			//we run a new iteration of dijkstra for this where we flip every edge on the SP
			//cout<<edges[bad].u<<" "<<edges[bad].v<<endl;
			
			al[edges[bad].v].push_back(E(-1,edges[bad].u,edges[bad].len,-1,-1));
			
			rep(x,0,205) w1[x]=w2[x]=INF;
			
			w1[1]=0;
			pq.push(ii(w1[1],1));
			while (!pq.empty()){
				temp=pq.top().first;
				node=pq.top().second;
				pq.pop();
				if (temp>w1[node]) continue; //important
				for (auto &it:al[node]){
					if (it.id==edges[bad].id) continue;
					if (w1[it.v]>w1[node]+it.len){
						w1[it.v]=w1[node]+it.len;
						pq.push(ii (w1[it.v],it.v));
					}
				}
			}
			
			w2[n]=0;
			pq.push(ii(w2[n],n));
			while (!pq.empty()){
				temp=pq.top().first;
				node=pq.top().second;
				pq.pop();
				if (temp>w2[node]) continue; //important
				for (auto &it:al[node]){
					if (it.id==edges[bad].id) continue;
					if (w2[it.v]>w2[node]+it.len){
						w2[it.v]=w2[node]+it.len;
						pq.push(ii (w2[it.v],it.v));
					}
				}
			}
			
			ans=min(ans,w1[n]+w2[1]+edges[bad].flip);
			al[edges[bad].v].pop_back();
		}
	}
	
	//find the path on best line from T->S
	if (tf[1]!=INF){
		rep(bad,0,m){
			//we run a new iteration of dijkstra for this where we flip every edge on the SP
			//cout<<edges[bad].u<<" "<<edges[bad].v<<endl;
			
			al[edges[bad].v].push_back(E(-1,edges[bad].u,edges[bad].len,-1,-1));
			
			rep(x,0,205) w1[x]=w2[x]=INF;
			
			w1[1]=0;
			pq.push(ii(w1[1],1));
			while (!pq.empty()){
				temp=pq.top().first;
				node=pq.top().second;
				pq.pop();
				if (temp>w1[node]) continue; //important
				for (auto &it:al[node]){
					if (it.id==edges[bad].id) continue;
					if (w1[it.v]>w1[node]+it.len){
						w1[it.v]=w1[node]+it.len;
						pq.push(ii (w1[it.v],it.v));
					}
				}
			}
			
			w2[n]=0;
			pq.push(ii(w2[n],n));
			while (!pq.empty()){
				temp=pq.top().first;
				node=pq.top().second;
				pq.pop();
				if (temp>w2[node]) continue; //important
				for (auto &it:al[node]){
					if (it.id==edges[bad].id) continue;
					if (w2[it.v]>w2[node]+it.len){
						w2[it.v]=w2[node]+it.len;
						pq.push(ii (w2[it.v],it.v));
					}
				}
			}
			
			ans=min(ans,w1[n]+w2[1]+edges[bad].flip);
			al[edges[bad].v].pop_back();
		}
	}
	
	if (ans>=INF) cout<<-1<<endl;
	else cout<<ans<<endl;
}

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 66 ms 512 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 97 ms 512 KB Output is correct
4 Correct 110 ms 512 KB Output is correct
5 Correct 35 ms 512 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 4 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 9 ms 512 KB Output is correct
10 Correct 155 ms 512 KB Output is correct
11 Correct 154 ms 512 KB Output is correct
12 Correct 159 ms 512 KB Output is correct
13 Incorrect 5 ms 512 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1097 ms 7012 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 69 ms 512 KB Output is correct
2 Correct 6 ms 384 KB Output is correct
3 Execution timed out 1091 ms 6644 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 66 ms 512 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 97 ms 512 KB Output is correct
4 Correct 110 ms 512 KB Output is correct
5 Correct 35 ms 512 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 4 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 9 ms 512 KB Output is correct
10 Correct 155 ms 512 KB Output is correct
11 Correct 154 ms 512 KB Output is correct
12 Correct 159 ms 512 KB Output is correct
13 Incorrect 5 ms 512 KB Output isn't correct
14 Halted 0 ms 0 KB -