oj.uz

Submission #939756

# Submission time Handle Problem Language Result Execution time Memory
939756 2024-03-06T17:40:10 Z vjudge1 One-Way Streets (CEOI17_oneway) C++17
60 / 100
 3000 ms 62776 KB 
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>

#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()

using namespace std;

int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
  
const int N = 1e5 + 10;


int low[N], h[N];
vector <int> g[N];
vector <int> gc[N];
int lead[N];
int vis[N], par[N];
int tin[N], tout[N], up[N][25], used[N];
int timer;

map <pair <int,int>, int > brid, was;

void dfsc(int v){
	vis[v] = 1;
	for(auto to : g[v]){
		if(vis[to] == 0 && !brid.count({v, to})){
			lead[to] = lead[v];
			dfsc(to);
		}
	}
}

void dfs_lca(int v, int p = 1) {
	tin[v] = ++timer;
	par[v] = p;
	up[v][0] = p;
	for (int i=1; i<=20; ++i)
		up[v][i] = up[up[v][i-1]][i-1];
	for (auto to : gc[v]) {
		if (to == p)continue;
		dfs_lca(to, v);
	}
	tout[v] = ++timer;
}

bool upper (int a, int b) {
	return tin[a] <= tin[b] && tout[a] >= tout[b];
}

int lca (int a, int b) {
	if (upper (a, b))  return a;
	if (upper (b, a))  return b;
	for (int i=20; i>=0; --i)
		if (! upper (up[a][i], b))
			a = up[a][i];
	return up[a][0];
}


void dfs_low(int v, int p){
    used[v] = true;
    tin[v] = low[v] = ++timer;
 
    for (auto u : g[v]){
        if (u == p) continue;
        if (used[u]){
            low[v] = min(low[v], tin[u]);
        }else{
            dfs_low(u, v);
            low[v] = min(low[v], low[u]);
            if (was[{v, u}] <=  1 && low[u] > tin[v]){
				brid[{v, u}] = 1;
				brid[{u, v}] = 1;
			}
        }
    }
}

main(){
	iostream::sync_with_stdio(false);  
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, m;
    cin >> n >> m;
    
    vector <pair <int,int> > road;
    for(int i = 0; i < m; i++){
		int a, b;
		cin >> a >> b;
		g[a].pb(b);
		g[b].pb(a);
		was[{a, b}]++;
		was[{b, a}]++;
		road.pb({a, b});
	}
    
    for(int i = 1;  i<= n; i++){
		if(!used[i])dfs_low(i, i);
	}
	
	for(int i = 1; i <= n; i++){
		if(lead[i] == 0){
			lead[i] = i;
			dfsc(i);
		}	
	}
	set <pair <int,int> > st;
	for(auto x : road){
		if(brid.count(x)){
			if(st.find(x) != st.end())return EXIT_FAILURE;
			st.insert(x);
			gc[lead[x.ff]].pb(lead[x.ss]);
			gc[lead[x.ss]].pb(lead[x.ff]);
		}
	}
	
	memset(used, 0, sizeof(used));
	for(int i = 1; i <= n; i++){
		if(par[i] == 0){
			dfs_lca(i, i);
		}
	}
	
	int p;
	cin >> p;
	map <pair <int,int>, int> mp;
	while(p--){
		int a, b;
		cin >> a >> b;
		a = lead[a];	
		b = lead[b];
		if(a == b)continue;
		int lc = lca(a, b);
		while(a != lc){
			//cout << "--"<<a << endl;
			//if(par[a] == 0)return EXIT_FAILURE;
			mp[{lead[a], par[lead[a]]}] = 1;
			a = par[lead[a]];
		}
		while(b != lc){
			//if(par[b] == 0)return EXIT_FAILURE;
			mp[{par[lead[b]], lead[b]}] = 1;
			b = par[lead[b]];
		}
	}
	for(auto x : road){
		int f = x.ff, s = x.ss;
		f = lead[f];
		s = lead[s];
		if(mp.count({f, s})){
			cout << 'R';
		}else if(mp.count({s, f})){
			cout << 'L';
		}else
			cout << 'B';
	}
}

Compilation message

oneway.cpp:85:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   85 | main(){
      | ^~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 11100 KB Output is correct
2 Correct 2 ms 11100 KB Output is correct
3 Correct 3 ms 11352 KB Output is correct
4 Correct 5 ms 11516 KB Output is correct
5 Correct 4 ms 11356 KB Output is correct
6 Correct 3 ms 11100 KB Output is correct
7 Correct 5 ms 11356 KB Output is correct
8 Correct 4 ms 11356 KB Output is correct
9 Correct 3 ms 11116 KB Output is correct
10 Correct 3 ms 11100 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 11100 KB Output is correct
2 Correct 2 ms 11100 KB Output is correct
3 Correct 3 ms 11352 KB Output is correct
4 Correct 5 ms 11516 KB Output is correct
5 Correct 4 ms 11356 KB Output is correct
6 Correct 3 ms 11100 KB Output is correct
7 Correct 5 ms 11356 KB Output is correct
8 Correct 4 ms 11356 KB Output is correct
9 Correct 3 ms 11116 KB Output is correct
10 Correct 3 ms 11100 KB Output is correct
11 Correct 119 ms 29352 KB Output is correct
12 Correct 139 ms 32496 KB Output is correct
13 Correct 177 ms 36548 KB Output is correct
14 Correct 276 ms 42600 KB Output is correct
15 Correct 261 ms 44164 KB Output is correct
16 Correct 442 ms 55924 KB Output is correct
17 Correct 696 ms 60940 KB Output is correct
18 Correct 421 ms 55872 KB Output is correct
19 Correct 670 ms 62776 KB Output is correct
20 Correct 133 ms 33764 KB Output is correct
21 Correct 128 ms 33204 KB Output is correct

Subtask #3
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 11100 KB Output is correct
2 Correct 2 ms 11100 KB Output is correct
3 Correct 3 ms 11352 KB Output is correct
4 Correct 5 ms 11516 KB Output is correct
5 Correct 4 ms 11356 KB Output is correct
6 Correct 3 ms 11100 KB Output is correct
7 Correct 5 ms 11356 KB Output is correct
8 Correct 4 ms 11356 KB Output is correct
9 Correct 3 ms 11116 KB Output is correct
10 Correct 3 ms 11100 KB Output is correct
11 Correct 119 ms 29352 KB Output is correct
12 Correct 139 ms 32496 KB Output is correct
13 Correct 177 ms 36548 KB Output is correct
14 Correct 276 ms 42600 KB Output is correct
15 Correct 261 ms 44164 KB Output is correct
16 Correct 442 ms 55924 KB Output is correct
17 Correct 696 ms 60940 KB Output is correct
18 Correct 421 ms 55872 KB Output is correct
19 Correct 670 ms 62776 KB Output is correct
20 Correct 133 ms 33764 KB Output is correct
21 Correct 128 ms 33204 KB Output is correct
22 Execution timed out 3018 ms 61476 KB Time limit exceeded
23 Halted 0 ms 0 KB -