oj.uz

Submission #224162

# Submission time Handle Problem Language Result Execution time Memory
224162 2020-04-17T08:59:51 Z oolimry Olympic Bus (JOI20_ho_t4) C++14
16 / 100
 119 ms 6632 KB 
#include <bits/stdc++.h>

using namespace std;
long long inf = (1LL << 56LL);

typedef pair<long long, long long> ii;
typedef vector<int> vi;
vector<ii> adj[205];
vector<ii> adjR[205];
long long dis[205];
long long dis1[205];
long long disn[205];
long long dis1R[205];
long long disnR[205];

int n, m; 

long long dij(int s, int t){
	fill(dis, dis + (n+3), inf);
	
	priority_queue<ii, vector<ii>, greater<ii> > dtr; /// use greater<int>
	dtr.push(ii(0,s));
    dis[s] = 0;
    ///first is minpath, second is vertex
    while(!dtr.empty()){
        ii cur = dtr.top();
        dtr.pop();
        for(int j = 0;j < (int) adj[cur.second].size();j++){
            ii nei = adj[cur.second][j];
            if(nei.first + cur.first < dis[nei.second]){
                dis[nei.second] = nei.first + cur.first;
                dtr.push(ii(dis[nei.second],nei.second));
            }
        }
    }
    return dis[t];
}

long long dijR(int s, int t){
	fill(dis, dis + (n+3), inf);
	
	priority_queue<ii, vector<ii>, greater<ii> > dtr; /// use greater<int>
	dtr.push(ii(0,s));
    dis[s] = 0;
    ///first is minpath, second is vertex
    while(!dtr.empty()){
        ii cur = dtr.top();
        dtr.pop();
        for(int j = 0;j < (int) adjR[cur.second].size();j++){
            ii nei = adjR[cur.second][j];
            if(nei.first + cur.first < dis[nei.second]){
                dis[nei.second] = nei.first + cur.first;
                dtr.push(ii(dis[nei.second],nei.second));
            }
        }
    }
    return dis[t];
}

struct edge{
	long long u; long long v; long long c; long long d;
};
vector<edge> edges;

void prin(long long ans){
	if(ans >= inf) ans = -1;
	cout << ans;
	exit(0);
}

void subtask1(){
	long long ans = dij(1, n)+ dij(n, 1);
	for(int i = 0;i < m;i++){
		for(int i = 1;i <= n;i++) adj[i].clear();
		
		long long res = 0;
		for(int j = 0;j < m;j++){
			edge e = edges[j];
			if(i == j){
				adj[e.v].push_back(ii(e.c,e.u));
				res += e.d;
			}
			else adj[e.u].push_back(ii(e.c,e.v));
		}
		//cout << dij(1,n) + dij(n,1) + res << "\n";
		ans = min(ans, dij(1,n) + dij(n,1) + res);
	}
	
	prin(ans);
}

map<ii, int> LIGHT;

struct node{
    vi adj;
    vi bac;
    bool vis = false;
    int sccNo = -1;
    int value = 0;
};

node g1[205];

stack<int> order;
void dfs(int i){
    if(g1[i].vis) return;
    g1[i].vis = true;
    for(int j = 0;j < (int) g1[i].adj.size();j++){
        dfs(g1[i].adj[j]);
    }
    order.push(i);
}

vector<int> scc;
void dfs2(int i){
    if(g1[i].vis) return;
    g1[i].vis = true;
    for(int j = 0;j < (int) g1[i].bac.size();j++){
        dfs2(g1[i].bac[j]);
    }
    scc.push_back(i);
}


vector<node> dag;
vector<node> gad;

vector<int> ADJ[205];
vector<int> JDA[205];
bool SB[205];
bool TB[205];

ii memo[205];
long long dp(int u, int s){
	if(u == s) return 1;
	if(memo[u] != ii(0,0)) return memo[u].first;
	ii res = ii(0,0);
	for(int v : JDA[u]){
		long long x = dp(v, s);
		if(x != 0){
			res.first += x;
			res.second = v;
		}
	}
	memo[u] = res;
	return res.first;
}

void subtask3(){
	for(edge e : edges){
		g1[e.u].adj.push_back(e.v);
		g1[e.v].bac.push_back(e.u);
	}
	
	for(int i = 1;i <= n;i++){
        dfs(i);
    }
    for(int i = 1;i <= n;i++){
        g1[i].vis = false;
    }
    int c = 0;
    while(!order.empty()){
        int u = order.top();
        order.pop();
        if(g1[u].vis) continue;
        scc.clear();
        dfs2(u);
        for(int i = 0;i < (int) scc.size();i++){
            //cout << scc[i] << " ";
            g1[scc[i]].sccNo = c;
        }
        c++;
        node nn;
        nn.value = scc.size();
        dag.push_back(nn);
        //cout << "\n";
    }
    typedef pair<int,int> ii;
    map<ii, int> edges;
    for(int i = 1;i <= n;i++){
        for(int j = 0;j <(int) g1[i].adj.size();j++){
            int v = g1[i].adj[j];
            if(g1[i].sccNo != g1[v].sccNo){
				ii x = ii(g1[i].sccNo,g1[v].sccNo);
                if(edges.find(x) == edges.end()) edges[x] = LIGHT[ii(i,v)];
                else edges[x] = min(edges[x], LIGHT[ii(i,v)]);
            }
        }
    }
    for(int i = 0;i < dag.size();i++){
		dag[i].adj.clear();
	}
	
    //cout << "\nedges\n";
    for(auto a : edges){
        ADJ[a.first.first].push_back(a.first.second);
        JDA[a.first.second].push_back(a.first.first);
        //cout << a.first.first << " " << a.first.second << "\n";
    }
    
    int s = 1, t = n;
    if(dij(s,t) < inf && dij(t,s) < inf){
		prin(0);
	}
	
    
    if(dij(s, t) >= inf){
		swap(s,t);
	}
	if(dij(s, t) >= inf) prin(inf);
	
	long long ans = inf;
	
	//cout << "\nbfs\n";
	//cout << g1[t].sccNo << ", " << g1[s].sccNo << "\n";
	queue<int> bfs;
	
	int S = g1[s].sccNo, T = g1[t].sccNo;
	if(S == T) prin(0);
	
	bfs.push(T);
	while(!bfs.empty()){
		int u = bfs.front();bfs.pop();
		if(TB[u]) break;
		//cout << "TB: " << u << "\n";
		TB[u] = true;
		for(int v : ADJ[u]){
			bfs.push(v);
		}
		
	}
	
	bfs.push(S);
	while(!bfs.empty()){
		int u = bfs.front();bfs.pop();
		if(SB[u]) break;
		SB[u] = true;
		for(int v : JDA[u]){
			bfs.push(v);
		}
	}
	
	//for(int i = 0;i < (int) dag.size();i++){
	//	cout << TB[i] << " " << SB[i] << "\n";
	//}
	
	dp(T, S);
	//cout << memo[T].first << " " << memo[T].second << "\n"; 
	set<ii> banned;
	if(memo[T].first == 1){
		int u = T;
		while(u != S){
			int v = memo[T].second;
			banned.insert(ii(v,u));
			u = v;
		}
	}
	for(auto a : edges){
		int u = a.first.first; int v = a.first.second;
        if(SB[u] && TB[v] && banned.find(ii(u,v)) == banned.end()){
			ans = min(ans, (long long) a.second);
			//cout << u << " " << v << " " << a.second << "\n";
		}
    }
	   
	prin(ans);
	///try to make a path from t to e
}

int main(){
	//freopen("i.txt","r",stdin);
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	bool ST3 = true;
	cin >> n >> m;
	for(int i = 0;i < m;i++){
		long long u, v, c, d; cin >> u >> v >> c >> d;
		edges.push_back({u,v,c,d});
		adj[u].push_back(ii(c,v));
		adjR[v].push_back(ii(c,u));
		if(c != 0) ST3 = false;
		
		if(LIGHT.find(ii(u,v)) == LIGHT.end()) LIGHT[ii(u,v)] = d;
		else{
			LIGHT[ii(u,v)] = min( (long long) LIGHT[ii(u,v)], (long long) d);
		}
	}
	
	if(m <= 1000) subtask1();
	if(ST3) subtask3();
	else{
	
		dij(1,n);
		for(int i = 1;i <= n;i++) dis1[i] = dis[i];
		
		dij(n,1);
		for(int i = 1;i <= n;i++) disn[i] = dis[i];
		
		dijR(1,n);
		for(int i = 1;i <= n;i++) dis1R[i] = dis[i];
		
		dijR(n,1);
		for(int i = 1;i <= n;i++) disnR[i] = dis[i];
		
		long long ans = dis1[n] + disn[1];
		for(edge e : edges){
			///edge goes v -> u
			ans = min(ans, e.d + dis1[n] + disn[e.v] + dis1R[e.u] + e.c);
			ans = min(ans, e.d + disn[1] + dis1[e.v] + disnR[e.u] + e.c);
			ans = min(ans, e.d + dis1[e.v] + disnR[e.u] + disn[e.v] + dis1R[e.u] + 2 * e.c);
		}
		
		prin(ans);
	}
}

Compilation message

ho_t4.cpp: In function 'void subtask3()':
ho_t4.cpp:190:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < dag.size();i++){
                   ~~^~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 48 ms 512 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 68 ms 512 KB Output is correct
4 Correct 72 ms 512 KB Output is correct
5 Correct 36 ms 512 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 384 KB Output is correct
9 Correct 18 ms 512 KB Output is correct
10 Correct 101 ms 512 KB Output is correct
11 Correct 103 ms 604 KB Output is correct
12 Correct 119 ms 592 KB Output is correct
13 Correct 41 ms 488 KB Output is correct
14 Correct 54 ms 512 KB Output is correct
15 Correct 49 ms 544 KB Output is correct
16 Correct 52 ms 620 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 54 ms 5608 KB Output is correct
2 Correct 51 ms 5612 KB Output is correct
3 Correct 51 ms 6248 KB Output is correct
4 Correct 7 ms 640 KB Output is correct
5 Correct 47 ms 512 KB Output is correct
6 Correct 9 ms 512 KB Output is correct
7 Correct 8 ms 512 KB Output is correct
8 Correct 5 ms 384 KB Output is correct
9 Correct 51 ms 5992 KB Output is correct
10 Correct 50 ms 5992 KB Output is correct
11 Correct 49 ms 5868 KB Output is correct
12 Correct 50 ms 5864 KB Output is correct
13 Correct 56 ms 5868 KB Output is correct
14 Correct 50 ms 6248 KB Output is correct

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 49 ms 512 KB Output is correct
2 Correct 7 ms 384 KB Output is correct
3 Correct 41 ms 5484 KB Output is correct
4 Correct 6 ms 384 KB Output is correct
5 Correct 52 ms 6632 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 4 ms 384 KB Output is correct
8 Incorrect 55 ms 6504 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 48 ms 512 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 68 ms 512 KB Output is correct
4 Correct 72 ms 512 KB Output is correct
5 Correct 36 ms 512 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 384 KB Output is correct
9 Correct 18 ms 512 KB Output is correct
10 Correct 101 ms 512 KB Output is correct
11 Correct 103 ms 604 KB Output is correct
12 Correct 119 ms 592 KB Output is correct
13 Correct 41 ms 488 KB Output is correct
14 Correct 54 ms 512 KB Output is correct
15 Correct 49 ms 544 KB Output is correct
16 Correct 52 ms 620 KB Output is correct
17 Correct 54 ms 5608 KB Output is correct
18 Correct 51 ms 5612 KB Output is correct
19 Correct 51 ms 6248 KB Output is correct
20 Correct 7 ms 640 KB Output is correct
21 Correct 47 ms 512 KB Output is correct
22 Correct 9 ms 512 KB Output is correct
23 Correct 8 ms 512 KB Output is correct
24 Correct 5 ms 384 KB Output is correct
25 Correct 51 ms 5992 KB Output is correct
26 Correct 50 ms 5992 KB Output is correct
27 Correct 49 ms 5868 KB Output is correct
28 Correct 50 ms 5864 KB Output is correct
29 Correct 56 ms 5868 KB Output is correct
30 Correct 50 ms 6248 KB Output is correct
31 Correct 49 ms 512 KB Output is correct
32 Correct 7 ms 384 KB Output is correct
33 Correct 41 ms 5484 KB Output is correct
34 Correct 6 ms 384 KB Output is correct
35 Correct 52 ms 6632 KB Output is correct
36 Correct 5 ms 384 KB Output is correct
37 Correct 4 ms 384 KB Output is correct
38 Incorrect 55 ms 6504 KB Output isn't correct
39 Halted 0 ms 0 KB -