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Submission #701119

# Submission time Handle Problem Language Result Execution time Memory
701119 2023-02-20T06:44:17 Z Darren0724 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 72 ms 16992 KB 
#include <bits/stdc++.h>
using namespace std;

const int mxN=1e5;
int n, m, k, a[mxN], b[mxN], ab[mxN], d[mxN], s[mxN], p[mxN], r[mxN], dt=1, tin[mxN], low[mxN];
bool bg[mxN];
vector<int> adj[mxN];

int find(int x) {
	return x==p[x]?x:(p[x]=find(p[x]));
}

inline void join(int x, int y) {
	if((x=find(x))==(y=find(y)))
		return;
	if(r[x]<r[y])
		p[x]=y;
	else
		p[y]=x;
	if(r[x]==r[y])
		++r[x];
}

void dfs1(int u, int p) {
	tin[u]=low[u]=dt++;
	for(int e : adj[u]) {
		int v=u^ab[e];
		if(!tin[v]) {
			dfs1(v, e);
			low[u]=min(low[v], low[u]);
			if(low[v]>tin[u])
				bg[e]=1;
		} else if(e!=p)
			low[u]=min(tin[v], low[u]);
	}
}

void dfs2(int u, int p) {
	for(int e : adj[u]) {
		int v=u^ab[e];
		if(v==p)
			continue;
		d[v]=d[u]+1;
		dfs2(v, u);
		s[u]+=s[v];
	}
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	cin >> n >> m;
	for(int i=0; i<n; ++i)
		p[i]=i;
	for(int i=0; i<m; ++i) {
		cin >> a[i] >> b[i], --a[i], --b[i];
		ab[i]=a[i]^b[i];
		adj[a[i]].push_back(i);
		adj[b[i]].push_back(i);
	}
	for(int i=0; i<n; ++i)
		if(!tin[i])
			dfs1(i, -1);
	for(int i=0; i<m; ++i)
		if(!bg[i])
			join(a[i], b[i]);
	for(int i=0; i<n; ++i)
		adj[i].clear();
	for(int i=0; i<m; ++i) {
		if(!bg[i])
			continue;
		a[i]=find(a[i]);
		b[i]=find(b[i]);
		ab[i]=a[i]^b[i];
		adj[a[i]].push_back(i);
		adj[b[i]].push_back(i);
	}
	cin >> k;
	while(k--) {
		int x, y;
		cin >> x >> y, --x, --y;
		++s[find(x)], --s[find(y)];
	}
	for(int i=0; i<n; ++i) {
		if(p[i]==i&&!d[i]) {
			d[i]=1;
			dfs2(i, -1);
		}
	}
	for(int i=0; i<m; ++i) {
		if(!bg[i]) {
			cout << 'B';
			continue;
		}
        assert(abs(d[a[i]]-d[b[i]])==1);
		int u=d[a[i]]>d[b[i]]?a[i]:b[i];
		cout << (s[u]?((s[u]>0)==(u==a[i])?'R':'L'):'B');
	}
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2772 KB Output is correct
4 Correct 2 ms 2772 KB Output is correct
5 Correct 2 ms 2772 KB Output is correct
6 Correct 2 ms 2772 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2772 KB Output is correct
4 Correct 2 ms 2772 KB Output is correct
5 Correct 2 ms 2772 KB Output is correct
6 Correct 2 ms 2772 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct
11 Correct 32 ms 8308 KB Output is correct
12 Correct 40 ms 9640 KB Output is correct
13 Correct 42 ms 11184 KB Output is correct
14 Correct 63 ms 12428 KB Output is correct
15 Correct 54 ms 12792 KB Output is correct
16 Correct 57 ms 10388 KB Output is correct
17 Correct 55 ms 12244 KB Output is correct
18 Correct 61 ms 10264 KB Output is correct
19 Correct 48 ms 13644 KB Output is correct
20 Correct 37 ms 9104 KB Output is correct
21 Correct 34 ms 9388 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2772 KB Output is correct
4 Correct 2 ms 2772 KB Output is correct
5 Correct 2 ms 2772 KB Output is correct
6 Correct 2 ms 2772 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2772 KB Output is correct
11 Correct 32 ms 8308 KB Output is correct
12 Correct 40 ms 9640 KB Output is correct
13 Correct 42 ms 11184 KB Output is correct
14 Correct 63 ms 12428 KB Output is correct
15 Correct 54 ms 12792 KB Output is correct
16 Correct 57 ms 10388 KB Output is correct
17 Correct 55 ms 12244 KB Output is correct
18 Correct 61 ms 10264 KB Output is correct
19 Correct 48 ms 13644 KB Output is correct
20 Correct 37 ms 9104 KB Output is correct
21 Correct 34 ms 9388 KB Output is correct
22 Correct 66 ms 13388 KB Output is correct
23 Correct 72 ms 11436 KB Output is correct
24 Correct 71 ms 11536 KB Output is correct
25 Correct 64 ms 16992 KB Output is correct
26 Correct 62 ms 12864 KB Output is correct
27 Correct 66 ms 11532 KB Output is correct
28 Correct 27 ms 6220 KB Output is correct
29 Correct 55 ms 9820 KB Output is correct
30 Correct 53 ms 10492 KB Output is correct
31 Correct 52 ms 10252 KB Output is correct
32 Correct 55 ms 13464 KB Output is correct