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Submission #130973

# Submission time Handle Problem Language Result Execution time Memory
130973 2019-07-16T10:34:26 Z maruii One-Way Streets (CEOI17_oneway) C++14
100 / 100
 281 ms 21472 KB 
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
#define ff first
#define ss second

int N, M, P;
vector<pair<pii, bool> > edge[100005];
int dfn[100005], dfnn, low[100005];
char ans[100005];
bool vis[100005];

void dfs(int x) {
	low[x] = dfn[x] = ++dfnn;
	for (auto i : edge[x]) {
		if (dfn[i.ff.ff]) {
			if (!vis[i.ff.ss]) low[x] = min(low[x], dfn[i.ff.ff]);
			vis[i.ff.ss] = 1;
			continue;
		}
		vis[i.ff.ss] = 1;
		dfs(i.ff.ff);
		low[x] = min(low[x], low[i.ff.ff]);
	}
}

int cn, cpn[100005], dep[100005], spt[17][100005];
pii par[100005];
bool dir[100005];

void dfs2(int x, int c) {
	cpn[x] = c;
	vis[x] = 1;
	for (auto i : edge[x]) {
		if (vis[i.ff.ff]) continue;
		if (low[i.ff.ff] == dfn[i.ff.ff]) {
			dep[++cn] = dep[c] + 1;
			par[cn] = pii(c, i.ff.ss);
			dir[cn] = i.ss;
			spt[0][cn] = c;
			dfs2(i.ff.ff, cn);
		}
		else dfs2(i.ff.ff, c);
	}
}

int upa[100005];
int fnd(int x) {return x == upa[x] ? x : upa[x] = fnd(upa[x]);}
void uni(int x, int y) {
	x = fnd(x), y = fnd(y);
	if (x == y) return;
	upa[y] = x;
}

int lca(int x, int y) {
	if (dep[x] < dep[y]) swap(x, y);
	for (int i = 16; i >= 0; --i) if (dep[spt[i][x]] >= dep[y]) x = spt[i][x];
	if (x == y) return x;
	for (int i = 16; i >= 0; --i) if (spt[i][x] != spt[i][y]) x = spt[i][x], y = spt[i][y];
	return spt[0][x];	
}

int main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	cin >> N >> M;
	for (int i = 0; i < M; ++i) {
		int x, y; cin >> x >> y;
		edge[x].emplace_back(pii(y, i), 1);
		edge[y].emplace_back(pii(x, i), 0);
	}
	
	for (int i = 1; i <= N; ++i) if (!dfn[i]) dfs(i);
	memset(vis, 0, sizeof(vis));
	for (int i = 1; i <= N; ++i) if (!vis[i]) dep[++cn] = 1, dfs2(i, cn);
	for (int i = 1; i < 17; ++i) for (int j = 1; j <= cn; ++j) spt[i][j] = spt[i-1][spt[i-1][j]];
	iota(upa, upa + cn + 1, 0);

	cin >> P;
	for (int i = 0; i < P; ++i) {
		int x, y; cin >> x >> y;
		x = cpn[x], y = cpn[y];
		int l = lca(x, y);
		for (int v = x; dep[par[fnd(v)].ff] >= dep[l]; ans[par[fnd(v)].ss] = (dir[fnd(v)] ? 'L' : 'R'), uni(par[fnd(v)].ff, v), v = fnd(v));
		for (int v = y; dep[par[fnd(v)].ff] >= dep[l]; ans[par[fnd(v)].ss] = (dir[fnd(v)] ? 'R' : 'L'), uni(par[fnd(v)].ff, v), v = fnd(v)); 
	}
	for (int i = 0; i < M; ++i) cout << ((ans[i] != 'L' && ans[i] != 'R') ? 'B' : ans[i]);
	return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2936 KB Output is correct
2 Correct 4 ms 2936 KB Output is correct
3 Correct 4 ms 2936 KB Output is correct
4 Correct 5 ms 3064 KB Output is correct
5 Correct 5 ms 3064 KB Output is correct
6 Correct 5 ms 2936 KB Output is correct
7 Correct 5 ms 3068 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 5 ms 2936 KB Output is correct
10 Correct 4 ms 2936 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2936 KB Output is correct
2 Correct 4 ms 2936 KB Output is correct
3 Correct 4 ms 2936 KB Output is correct
4 Correct 5 ms 3064 KB Output is correct
5 Correct 5 ms 3064 KB Output is correct
6 Correct 5 ms 2936 KB Output is correct
7 Correct 5 ms 3068 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 5 ms 2936 KB Output is correct
10 Correct 4 ms 2936 KB Output is correct
11 Correct 61 ms 8944 KB Output is correct
12 Correct 64 ms 9616 KB Output is correct
13 Correct 79 ms 10688 KB Output is correct
14 Correct 81 ms 13048 KB Output is correct
15 Correct 83 ms 14072 KB Output is correct
16 Correct 91 ms 17856 KB Output is correct
17 Correct 79 ms 18680 KB Output is correct
18 Correct 92 ms 17880 KB Output is correct
19 Correct 85 ms 19340 KB Output is correct
20 Correct 60 ms 9084 KB Output is correct
21 Correct 56 ms 9080 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2936 KB Output is correct
2 Correct 4 ms 2936 KB Output is correct
3 Correct 4 ms 2936 KB Output is correct
4 Correct 5 ms 3064 KB Output is correct
5 Correct 5 ms 3064 KB Output is correct
6 Correct 5 ms 2936 KB Output is correct
7 Correct 5 ms 3068 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 5 ms 2936 KB Output is correct
10 Correct 4 ms 2936 KB Output is correct
11 Correct 61 ms 8944 KB Output is correct
12 Correct 64 ms 9616 KB Output is correct
13 Correct 79 ms 10688 KB Output is correct
14 Correct 81 ms 13048 KB Output is correct
15 Correct 83 ms 14072 KB Output is correct
16 Correct 91 ms 17856 KB Output is correct
17 Correct 79 ms 18680 KB Output is correct
18 Correct 92 ms 17880 KB Output is correct
19 Correct 85 ms 19340 KB Output is correct
20 Correct 60 ms 9084 KB Output is correct
21 Correct 56 ms 9080 KB Output is correct
22 Correct 277 ms 19832 KB Output is correct
23 Correct 227 ms 18808 KB Output is correct
24 Correct 227 ms 18956 KB Output is correct
25 Correct 206 ms 21472 KB Output is correct
26 Correct 207 ms 19740 KB Output is correct
27 Correct 281 ms 18848 KB Output is correct
28 Correct 56 ms 7160 KB Output is correct
29 Correct 115 ms 10076 KB Output is correct
30 Correct 99 ms 10152 KB Output is correct
31 Correct 100 ms 10280 KB Output is correct
32 Correct 154 ms 13944 KB Output is correct