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Submission #130974

# Submission time Handle Problem Language Result Execution time Memory
130974 2019-07-16T10:36:07 Z maruii One-Way Streets (CEOI17_oneway) C++14
100 / 100
 263 ms 19324 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 2940 KB Output is correct
3 Correct 5 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 3064 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 6 ms 2936 KB Output is correct
10 Correct 5 ms 3064 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 2940 KB Output is correct
3 Correct 5 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 3064 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 6 ms 2936 KB Output is correct
10 Correct 5 ms 3064 KB Output is correct
11 Correct 58 ms 8028 KB Output is correct
12 Correct 82 ms 8580 KB Output is correct
13 Correct 76 ms 9696 KB Output is correct
14 Correct 88 ms 12024 KB Output is correct
15 Correct 81 ms 12992 KB Output is correct
16 Correct 88 ms 16760 KB Output is correct
17 Correct 78 ms 17656 KB Output is correct
18 Correct 89 ms 16888 KB Output is correct
19 Correct 105 ms 18268 KB Output is correct
20 Correct 61 ms 8184 KB Output is correct
21 Correct 57 ms 8056 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 2940 KB Output is correct
3 Correct 5 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 3064 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 6 ms 2936 KB Output is correct
10 Correct 5 ms 3064 KB Output is correct
11 Correct 58 ms 8028 KB Output is correct
12 Correct 82 ms 8580 KB Output is correct
13 Correct 76 ms 9696 KB Output is correct
14 Correct 88 ms 12024 KB Output is correct
15 Correct 81 ms 12992 KB Output is correct
16 Correct 88 ms 16760 KB Output is correct
17 Correct 78 ms 17656 KB Output is correct
18 Correct 89 ms 16888 KB Output is correct
19 Correct 105 ms 18268 KB Output is correct
20 Correct 61 ms 8184 KB Output is correct
21 Correct 57 ms 8056 KB Output is correct
22 Correct 263 ms 17608 KB Output is correct
23 Correct 240 ms 16696 KB Output is correct
24 Correct 216 ms 16892 KB Output is correct
25 Correct 213 ms 19324 KB Output is correct
26 Correct 199 ms 17400 KB Output is correct
27 Correct 191 ms 16724 KB Output is correct
28 Correct 53 ms 6136 KB Output is correct
29 Correct 95 ms 7928 KB Output is correct
30 Correct 93 ms 7960 KB Output is correct
31 Correct 96 ms 8184 KB Output is correct
32 Correct 158 ms 11768 KB Output is correct