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Submission #711246

# Submission time Handle Problem Language Result Execution time Memory
711246 2023-03-16T11:06:57 Z WonderfulWhale One-Way Streets (CEOI17_oneway) C++17
100 / 100
 144 ms 42192 KB 
#include<bits/stdc++.h>
using namespace std;

#define int int64_t
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()

const int MAXN = 100009;
const int LOG = 17;

int n, m;
int jump[MAXN];
bool bridge[MAXN];
int dep[MAXN];
vector<pii> G[MAXN];
vector<pii> G2[MAXN];
int S[MAXN];
int E[MAXN];
pii edge[MAXN];
int ans[MAXN];
bool vis[MAXN];
int tab[MAXN];
int cnt;
int T, tin[MAXN], tout[MAXN], jp2[MAXN][LOG];

void dfs1(int x, int d, int pre) {
	vis[x] = true;
	dep[x] = d;
	jump[x] = d;
	for(auto [z, id]:G[x]) {
		if(id==pre) continue;
		if(!vis[z]) {
			dfs1(z, d+1, id);
			jump[x] = min(jump[x], jump[z]);
		} else {
			jump[x] = min(jump[x], dep[z]);
		}
	}
	if(pre==-1) return;
	if(jump[x] == d) bridge[pre] = true;
}

void dfs2(int x, int col) {
	vis[x] = true;
	tab[x] = col;
	for(auto [z, id]:G[x]) {
		if(!bridge[id]) {
			if(!vis[z]) dfs2(z, col);
		} else {
			if(vis[z]) {
				G2[col].pb({tab[z], id});
			} else {
				dfs2(z, ++cnt);
				G2[col].pb({tab[z], id});
			}
		}
	}
}

void dfs3(int x, int y) {
	vis[x] = true;
	tin[x] = ++T;
	jp2[x][0] = y;
	for(int i=1;i<LOG;i++) {
		jp2[x][i] = jp2[jp2[x][i-1]][i-1];
	}
	for(auto [z, id]:G2[x]) {
		if(z!=y) dfs3(z, x);
	}
	tout[x] = ++T;
}

bool is_ancestor(int x, int y) {
	return tin[x]<=tin[y]&&tout[x]>=tout[y];
}

int lca(int x, int y) {
	if(is_ancestor(x, y)) return x;
	if(is_ancestor(y, x)) return y;
	for(int i=LOG-1;i>=0;i--) {
		if(!is_ancestor(jp2[x][i], y)) {
			x = jp2[x][i];
		}
	}
	return jp2[x][0];
}

pii dfs4(int x, int pre) {
	vis[x] = true;
	pii val = {0, 0};
	for(auto [z, id]:G2[x]) {
		if(id==pre) continue;
		pii nval = dfs4(z, id);
		val.st += nval.st;
		val.nd += nval.nd;
	}
	val.st += S[x];
	val.nd += E[x];
	if(pre==-1) return val;
	if(val.st) {
		if(x == tab[edge[pre].st]) {
			ans[pre] = -1;
		} else {
			ans[pre] = 1;
		}
	} else if(val.nd) {
		if(x == tab[edge[pre].st]) {
			ans[pre] = 1;
		} else {
			ans[pre] = -1;
		}
	}
	return val;
}

int32_t main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	cin >> n >> m;
	for(int i=0;i<m;i++) {
		int a, b;
		cin >> a >> b;
		G[a].pb({b, i});
		G[b].pb({a, i});
		edge[i] = {a, b};
	}
	for(int i=1;i<=n;i++) {
		if(!vis[i]) {
			dfs1(i, 0, -1);
		}
	}
	memset(vis, 0, sizeof(vis));
	for(int i=1;i<=n;i++) {
		if(!vis[i]) {
			dfs2(i, ++cnt);
		}
	}
	memset(vis, 0, sizeof(vis));
	for(int i=1;i<=cnt;i++) {
		if(!vis[i]) {
			dfs3(i, 0);
		}
	}
	tin[0] = 0;
	tout[0] = ++T;
	int q;
	cin >> q;
	while(q--) {
		int a, b;
		cin >> a >> b;
		S[tab[a]]++;
		E[tab[b]]++;
		int Lca = lca(tab[a], tab[b]);
		S[Lca]--;
		E[Lca]--;
	}
	memset(vis, 0, sizeof(vis));
	for(int i=1;i<=cnt;i++) {
		if(!vis[i]) {
			dfs4(i, -1);
		}
	}
	for(int i=0;i<m;i++) {
		if(ans[i]==0) {
			cout << "B";
		} else if(ans[i]==1) {
			cout << "L";
		} else {
			cout << "R";
		}
	}
	cout << "\n";
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5076 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 4 ms 5300 KB Output is correct
4 Correct 5 ms 5588 KB Output is correct
5 Correct 4 ms 5460 KB Output is correct
6 Correct 4 ms 5204 KB Output is correct
7 Correct 5 ms 5428 KB Output is correct
8 Correct 4 ms 5460 KB Output is correct
9 Correct 3 ms 5204 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5076 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 4 ms 5300 KB Output is correct
4 Correct 5 ms 5588 KB Output is correct
5 Correct 4 ms 5460 KB Output is correct
6 Correct 4 ms 5204 KB Output is correct
7 Correct 5 ms 5428 KB Output is correct
8 Correct 4 ms 5460 KB Output is correct
9 Correct 3 ms 5204 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct
11 Correct 38 ms 13832 KB Output is correct
12 Correct 43 ms 15156 KB Output is correct
13 Correct 69 ms 17132 KB Output is correct
14 Correct 71 ms 22168 KB Output is correct
15 Correct 79 ms 24428 KB Output is correct
16 Correct 87 ms 34536 KB Output is correct
17 Correct 84 ms 37708 KB Output is correct
18 Correct 93 ms 35532 KB Output is correct
19 Correct 83 ms 39348 KB Output is correct
20 Correct 43 ms 14416 KB Output is correct
21 Correct 42 ms 15028 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5076 KB Output is correct
2 Correct 3 ms 5076 KB Output is correct
3 Correct 4 ms 5300 KB Output is correct
4 Correct 5 ms 5588 KB Output is correct
5 Correct 4 ms 5460 KB Output is correct
6 Correct 4 ms 5204 KB Output is correct
7 Correct 5 ms 5428 KB Output is correct
8 Correct 4 ms 5460 KB Output is correct
9 Correct 3 ms 5204 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct
11 Correct 38 ms 13832 KB Output is correct
12 Correct 43 ms 15156 KB Output is correct
13 Correct 69 ms 17132 KB Output is correct
14 Correct 71 ms 22168 KB Output is correct
15 Correct 79 ms 24428 KB Output is correct
16 Correct 87 ms 34536 KB Output is correct
17 Correct 84 ms 37708 KB Output is correct
18 Correct 93 ms 35532 KB Output is correct
19 Correct 83 ms 39348 KB Output is correct
20 Correct 43 ms 14416 KB Output is correct
21 Correct 42 ms 15028 KB Output is correct
22 Correct 144 ms 37996 KB Output is correct
23 Correct 123 ms 35912 KB Output is correct
24 Correct 141 ms 36044 KB Output is correct
25 Correct 124 ms 42192 KB Output is correct
26 Correct 143 ms 37540 KB Output is correct
27 Correct 141 ms 36224 KB Output is correct
28 Correct 31 ms 11032 KB Output is correct
29 Correct 65 ms 14032 KB Output is correct
30 Correct 61 ms 14472 KB Output is correct
31 Correct 66 ms 14388 KB Output is correct
32 Correct 89 ms 23876 KB Output is correct