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Submission #711245

# Submission time Handle Problem Language Result Execution time Memory
711245 2023-03-16T11:05:50 Z WonderfulWhale One-Way Streets (CEOI17_oneway) C++17
100 / 100
 153 ms 44328 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;
	//cout << "teraz: " << x << " skok: " << jump[x] << "\n";
	//cout << pre << " " << bridge[pre] << "\n";
}

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) {
	//cout << "licze: " << x << " " << y << "\n";
	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];
	//cout << "v: " << x << " " << val.st << " " << val.nd << "\n";
	assert(!val.st||!val.nd);
	if(pre==-1) return val;
	if(val.st) {
		//cout << "tu: " << x << " "<< tab[edge[pre].st] << "\n";
		if(x == tab[edge[pre].st]) {
			//cout << "set: " << pre << " 1\n";
			ans[pre] = -1;
		} else {
			//cout << "set: " << pre << " 2\n";
			ans[pre] = 1;
		}
	} else if(val.nd) {
		//cout << "tu\n";
		if(x == tab[edge[pre].st]) {
			//cout << "set: " << pre << " 3\n";
			ans[pre] = 1;
		} else {
			//cout << "set: " << pre << " 4\n";
			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);
		}
	}
	for(int i=1;i<=n;i++) {
		//cout << i << ": " << tab[i] << "\n";
	}
	//cout << "graf\n";
	for(int i=1;i<=cnt;i++) {
		//cout << i << ":\n";
		for(pii x:G2[i]) {
			//cout << x.st << " " << x.nd << "\n";
		}
	}
	//cout << "koniec\n";
	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]);
		//cout << tab[a] << " " << tab[b] << " " << Lca << " lca\n";
		S[Lca]--;
		E[Lca]--;
	}
	for(int i=1;i<=cnt;i++) {
		//cout << i << ": "<< S[i] << " " << E[i] << "\n";
	}
	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";
}

Compilation message

oneway.cpp: In function 'int32_t main()':
oneway.cpp:160:11: warning: variable 'x' set but not used [-Wunused-but-set-variable]
  160 |   for(pii x:G2[i]) {
      |           ^

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 5204 KB Output is correct
4 Correct 4 ms 5420 KB Output is correct
5 Correct 5 ms 5424 KB Output is correct
6 Correct 4 ms 5292 KB Output is correct
7 Correct 4 ms 5420 KB Output is correct
8 Correct 4 ms 5460 KB Output is correct
9 Correct 3 ms 5292 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 5204 KB Output is correct
4 Correct 4 ms 5420 KB Output is correct
5 Correct 5 ms 5424 KB Output is correct
6 Correct 4 ms 5292 KB Output is correct
7 Correct 4 ms 5420 KB Output is correct
8 Correct 4 ms 5460 KB Output is correct
9 Correct 3 ms 5292 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct
11 Correct 40 ms 14788 KB Output is correct
12 Correct 45 ms 16096 KB Output is correct
13 Correct 55 ms 18184 KB Output is correct
14 Correct 92 ms 23192 KB Output is correct
15 Correct 83 ms 25536 KB Output is correct
16 Correct 88 ms 35572 KB Output is correct
17 Correct 87 ms 38756 KB Output is correct
18 Correct 94 ms 36784 KB Output is correct
19 Correct 95 ms 40468 KB Output is correct
20 Correct 52 ms 15328 KB Output is correct
21 Correct 41 ms 16092 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 5204 KB Output is correct
4 Correct 4 ms 5420 KB Output is correct
5 Correct 5 ms 5424 KB Output is correct
6 Correct 4 ms 5292 KB Output is correct
7 Correct 4 ms 5420 KB Output is correct
8 Correct 4 ms 5460 KB Output is correct
9 Correct 3 ms 5292 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct
11 Correct 40 ms 14788 KB Output is correct
12 Correct 45 ms 16096 KB Output is correct
13 Correct 55 ms 18184 KB Output is correct
14 Correct 92 ms 23192 KB Output is correct
15 Correct 83 ms 25536 KB Output is correct
16 Correct 88 ms 35572 KB Output is correct
17 Correct 87 ms 38756 KB Output is correct
18 Correct 94 ms 36784 KB Output is correct
19 Correct 95 ms 40468 KB Output is correct
20 Correct 52 ms 15328 KB Output is correct
21 Correct 41 ms 16092 KB Output is correct
22 Correct 132 ms 40256 KB Output is correct
23 Correct 129 ms 38208 KB Output is correct
24 Correct 143 ms 38220 KB Output is correct
25 Correct 121 ms 44328 KB Output is correct
26 Correct 145 ms 39828 KB Output is correct
27 Correct 153 ms 38356 KB Output is correct
28 Correct 35 ms 12120 KB Output is correct
29 Correct 61 ms 16076 KB Output is correct
30 Correct 65 ms 16608 KB Output is correct
31 Correct 66 ms 16588 KB Output is correct
32 Correct 99 ms 25952 KB Output is correct