oj.uz

Submission #45093

# Submission time Handle Problem Language Result Execution time Memory
45093 2018-04-11T08:07:33 Z qoo2p5 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 309 ms 53444 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int INF = (int) 1e9 + 1e6 + 123;
const ll LINF = (ll) 1e18 + 1e9 + 123;

#define rep(i, s, t) for (auto i = (s); i < (t); ++(i))
#define per(i, s, t) for (auto i = (s); i >= (t); --(i))
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define mp make_pair
#define pb push_back

bool mini(auto &x, const auto &y) {
	if (y < x) {
		x = y;
		return 1;
	}
	return 0;
}

bool maxi(auto &x, const auto &y) {
	if (y > x) {
		x = y;
		return 1;
	}
	return 0;
}

void run();

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	run();
	return 0;
}

const int N = (int) 1e5 + 123;

struct E {
	int a, b;
};

int n, m;
E e[N];
vector<pair<int, int>> g[N];
bool vis[N];

int tmr;
int tin[N], fup[N];
bool is_bridge[N];

void dfs(int v, int from_id = -1) {
	tin[v] = tmr++;
	fup[v] = tin[v];
	vis[v] = 1;
	for (auto &it : g[v]) {
		if (it.second == from_id) {
			continue;
		}
		int u = it.first;
		if (vis[u]) {
			mini(fup[v], tin[u]);
		} else {
			dfs(u, it.second);
			mini(fup[v], fup[u]);
		}
	}
	
	for (auto &it : g[v]) {
		if (it.second == from_id) {
			continue;
		}
		int u = it.first;
		int id = it.second;
		if (fup[u] > tin[v]) {
			is_bridge[id] = 1;
		}
	}
}

int comps;
int which[N];
vector<pair<int, int>> adj[N];
char ans[N];

void find_comps(int v) {
	vis[v] = 1;
	which[v] = comps;
	for (auto &it : g[v]) {
		int u = it.first;
		int id = it.second;
		if (is_bridge[id]) {
			continue;
		}
		ans[id] = 'B';
		if (vis[u]) {
			continue;
		}
		find_comps(u);
	}
}

const int L = 20;
int up[N][L];
int depth[N];

void calc_lca(int v, int f = -1) {
	if (f == -1) {
		rep(i, 0, L) up[v][i] = v;
	} else {
		up[v][0] = f;
		rep(i, 1, L) up[v][i] = up[up[v][i - 1]][i - 1];
	}
	vis[v] = 1;
	for (auto &it : adj[v]) {
		int u = it.first;
		if (!vis[u]) {
			depth[u] = depth[v] + 1;
			calc_lca(u, v);
		}
	}
}

bool test(int mask, int bit) {
	return mask & (1 << bit);
}

int go(int v, int h) {
	rep(i, 0, L) if (test(h, i)) v = up[v][i];
	return v;
}

int lca(int u, int v) {
	if (depth[u] < depth[v]) swap(u, v);
	u = go(u, depth[u] - depth[v]);
	if (u == v) return u;
	per(i, L - 1, 0) {
		int uu = up[u][i];
		int vv = up[v][i];
		if (uu != vv) {
			u = uu, v = vv;
		}
	}
	return up[u][0];
}

int cnt_up[N], cnt_down[N];

void solve(int v, int fid = -1) {
	vis[v] = 1;
	for (auto &it : adj[v]) {
		int u = it.first;
		if (vis[u]) continue;
		solve(u, it.second);
		maxi(cnt_up[v], cnt_up[u] - 1);
		maxi(cnt_down[v], cnt_down[u] - 1);
	}
	
	assert(cnt_up[v] == 0 || cnt_down[v] == 0);
	if (fid != -1) {
		if (cnt_up[v] > 0) {
			if (which[e[fid].a] == v) {
				ans[fid] = 'R';
			} else {
				ans[fid] = 'L';
			}
		} else if (cnt_down[v] > 0) {
			if (which[e[fid].a] == v) {
				ans[fid] = 'L';
			} else {
				ans[fid] = 'R';
			}
		} else {
			ans[fid] = 'B';
		}
	}
}

void run() {
	cin >> n >> m;
	rep(i, 0, m) {
		cin >> e[i].a >> e[i].b;
		g[e[i].a].pb({e[i].b, i});
		g[e[i].b].pb({e[i].a, i});
	}
	
	rep(i, 1, n + 1) {
		if (!vis[i]) {
			dfs(i);
		}
	}
	memset(vis, 0, sizeof vis);
	rep(i, 1, n + 1) {
		if (!vis[i]) {
			find_comps(i);
			comps++;
		}
	}
	memset(vis, 0, sizeof vis);
	rep(i, 0, m) {
		int u = which[e[i].a];
		int v = which[e[i].b];
		if (u != v) {
			adj[u].pb({v, i});
			adj[v].pb({u, i});
		}
	}
	rep(i, 0, comps) {
		if (!vis[i]) {
			calc_lca(i);
		}
	}
	memset(vis, 0, sizeof vis);
	
	int p;
	cin >> p;
	while (p--) {
		int x, y;
		cin >> x >> y;
		x = which[x], y = which[y];
		if (x == y) {
			continue;
		}
		
		int w = lca(x, y);
		maxi(cnt_up[x], depth[x] - depth[w]);
		maxi(cnt_down[y], depth[y] - depth[w]);
	}
	
	rep(i, 0, comps) {
		if (!vis[i]) {
			solve(i);
		}
	}
	
	rep(i, 0, m) {
		cout << ans[i];
	}
	cout << "\n";
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5112 KB Output is correct
2 Correct 6 ms 5348 KB Output is correct
3 Correct 8 ms 5424 KB Output is correct
4 Correct 6 ms 5484 KB Output is correct
5 Correct 7 ms 5636 KB Output is correct
6 Correct 7 ms 5636 KB Output is correct
7 Correct 9 ms 5636 KB Output is correct
8 Correct 8 ms 5660 KB Output is correct
9 Correct 6 ms 5660 KB Output is correct
10 Correct 6 ms 5660 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5112 KB Output is correct
2 Correct 6 ms 5348 KB Output is correct
3 Correct 8 ms 5424 KB Output is correct
4 Correct 6 ms 5484 KB Output is correct
5 Correct 7 ms 5636 KB Output is correct
6 Correct 7 ms 5636 KB Output is correct
7 Correct 9 ms 5636 KB Output is correct
8 Correct 8 ms 5660 KB Output is correct
9 Correct 6 ms 5660 KB Output is correct
10 Correct 6 ms 5660 KB Output is correct
11 Correct 62 ms 11708 KB Output is correct
12 Correct 75 ms 13792 KB Output is correct
13 Correct 72 ms 16372 KB Output is correct
14 Correct 93 ms 20760 KB Output is correct
15 Correct 156 ms 23184 KB Output is correct
16 Correct 160 ms 30568 KB Output is correct
17 Correct 166 ms 33448 KB Output is correct
18 Correct 136 ms 33448 KB Output is correct
19 Correct 156 ms 36928 KB Output is correct
20 Correct 64 ms 36928 KB Output is correct
21 Correct 70 ms 36928 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5112 KB Output is correct
2 Correct 6 ms 5348 KB Output is correct
3 Correct 8 ms 5424 KB Output is correct
4 Correct 6 ms 5484 KB Output is correct
5 Correct 7 ms 5636 KB Output is correct
6 Correct 7 ms 5636 KB Output is correct
7 Correct 9 ms 5636 KB Output is correct
8 Correct 8 ms 5660 KB Output is correct
9 Correct 6 ms 5660 KB Output is correct
10 Correct 6 ms 5660 KB Output is correct
11 Correct 62 ms 11708 KB Output is correct
12 Correct 75 ms 13792 KB Output is correct
13 Correct 72 ms 16372 KB Output is correct
14 Correct 93 ms 20760 KB Output is correct
15 Correct 156 ms 23184 KB Output is correct
16 Correct 160 ms 30568 KB Output is correct
17 Correct 166 ms 33448 KB Output is correct
18 Correct 136 ms 33448 KB Output is correct
19 Correct 156 ms 36928 KB Output is correct
20 Correct 64 ms 36928 KB Output is correct
21 Correct 70 ms 36928 KB Output is correct
22 Correct 283 ms 40444 KB Output is correct
23 Correct 249 ms 41156 KB Output is correct
24 Correct 220 ms 43772 KB Output is correct
25 Correct 309 ms 50252 KB Output is correct
26 Correct 245 ms 50252 KB Output is correct
27 Correct 263 ms 50472 KB Output is correct
28 Correct 51 ms 50472 KB Output is correct
29 Correct 102 ms 50472 KB Output is correct
30 Correct 105 ms 50472 KB Output is correct
31 Correct 97 ms 50472 KB Output is correct
32 Correct 155 ms 53444 KB Output is correct