oj.uz

Submission #939945

# Submission time Handle Problem Language Result Execution time Memory
939945 2024-03-07T02:05:45 Z smartmonky One-Way Streets (CEOI17_oneway) C++14
100 / 100
 566 ms 70072 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], depth[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;
	depth[v] = depth[p] + 1;
	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;
	vector <pair <int, pair <int,int> > > l;
	while(p--){
		int a, b;
		cin >> a >> b;
		a = lead[a];	
		b = lead[b];
		if(a == b)continue;
		int lc = lca(a, b);
		l.pb({depth[lc], {a, b}});
	}
	sort(all(l));
	vector <int> d(n + 1, 0);
	int cnt = 0;
	for(auto x : l){
		int a = x.ss.ff, b = x.ss.ss;
		int lc = lca(a, b);
		while(a != lc && d[a] == 0){
			cnt++;
			d[a] = 1;
			mp[{lead[a], par[lead[a]]}] = 1;
			a = par[lead[a]];
		}
		while(b != lc && d[b] == 0){
			cnt++;
			d[b] = 1;
			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:86:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   86 | main(){
      | ^~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 11096 KB Output is correct
2 Correct 2 ms 11100 KB Output is correct
3 Correct 3 ms 11356 KB Output is correct
4 Correct 5 ms 11356 KB Output is correct
5 Correct 4 ms 11612 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 11096 KB Output is correct
10 Correct 3 ms 11096 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 11096 KB Output is correct
2 Correct 2 ms 11100 KB Output is correct
3 Correct 3 ms 11356 KB Output is correct
4 Correct 5 ms 11356 KB Output is correct
5 Correct 4 ms 11612 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 11096 KB Output is correct
10 Correct 3 ms 11096 KB Output is correct
11 Correct 135 ms 28288 KB Output is correct
12 Correct 162 ms 31664 KB Output is correct
13 Correct 175 ms 35668 KB Output is correct
14 Correct 284 ms 42120 KB Output is correct
15 Correct 282 ms 44084 KB Output is correct
16 Correct 428 ms 55508 KB Output is correct
17 Correct 431 ms 60816 KB Output is correct
18 Correct 447 ms 55496 KB Output is correct
19 Correct 402 ms 62400 KB Output is correct
20 Correct 137 ms 33212 KB Output is correct
21 Correct 139 ms 32368 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 11096 KB Output is correct
2 Correct 2 ms 11100 KB Output is correct
3 Correct 3 ms 11356 KB Output is correct
4 Correct 5 ms 11356 KB Output is correct
5 Correct 4 ms 11612 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 11096 KB Output is correct
10 Correct 3 ms 11096 KB Output is correct
11 Correct 135 ms 28288 KB Output is correct
12 Correct 162 ms 31664 KB Output is correct
13 Correct 175 ms 35668 KB Output is correct
14 Correct 284 ms 42120 KB Output is correct
15 Correct 282 ms 44084 KB Output is correct
16 Correct 428 ms 55508 KB Output is correct
17 Correct 431 ms 60816 KB Output is correct
18 Correct 447 ms 55496 KB Output is correct
19 Correct 402 ms 62400 KB Output is correct
20 Correct 137 ms 33212 KB Output is correct
21 Correct 139 ms 32368 KB Output is correct
22 Correct 490 ms 65208 KB Output is correct
23 Correct 506 ms 62632 KB Output is correct
24 Correct 566 ms 62456 KB Output is correct
25 Correct 456 ms 70072 KB Output is correct
26 Correct 513 ms 64448 KB Output is correct
27 Correct 506 ms 62404 KB Output is correct
28 Correct 47 ms 13512 KB Output is correct
29 Correct 174 ms 34560 KB Output is correct
30 Correct 181 ms 34720 KB Output is correct
31 Correct 147 ms 34192 KB Output is correct
32 Correct 239 ms 44464 KB Output is correct