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Submission #868396

# Submission time Handle Problem Language Result Execution time Memory
868396 2023-10-31T11:07:08 Z lovrot One-Way Streets (CEOI17_oneway) C++17
100 / 100
 67 ms 21756 KB 
#include <cstdio> 
#include <vector> 
#include <cstring> 

#define X first
#define Y second
#define MP make_pair
#define EB emplace_back

using namespace std;

typedef pair<int, int> pii;

const int N = 1e5 + 10;

int n, m, q, A[N], B[N];

int U[N];

int _find(int u) {
	if(U[u] == -1) return u;
	return U[u] = _find(U[u]);
}

void _union(int u, int v) {
	U[_find(u)] = _find(v);
}

int PE[N], DEP[N];
vector<pii> G[N];

int dfs(int u, int p) {	
	int sum = 0;
	for(pii e : G[u]) {	
		int v = e.X, ind = e.Y;
		if(ind == PE[u]) continue;
		else if(DEP[v] == -1) {
			DEP[v] = DEP[u] + 1;
			PE[v] = ind;
			sum += dfs(v, u);
		} else if(DEP[v] < DEP[u]) {
			++sum;
		} else if(DEP[v] > DEP[u]) { --sum; }
	}
	if(sum) _union(u, p);
	return sum;
}

int ANS[N], Q[N];
vector<pii> T[N];

void recon(int u, int p) {
	for(pii e : T[u]) {	
		int v = e.X, ind = e.Y;
		if(v != p) {
			PE[v] = ind;
			DEP[v] = DEP[u] + 1;
			recon(v, u);
		}
	}
}

int solve(int u, int p) {	
	int sum = Q[u];
	for(pii e : T[u]) {
		int v = e.X;
		if(v != p) {
			DEP[v] = DEP[u] + 1;
			sum += solve(v, u);
		}
	}
	if(sum < 0) ANS[PE[u]] = u == B[PE[u]];
	else if(sum > 0) ANS[PE[u]] = p == B[PE[u]];
	return sum;
}

int main() {
	memset(U, -1, sizeof(U));
	memset(DEP, -1, sizeof(DEP)); 
	memset(ANS, -1, sizeof(ANS));

	scanf("%d%d", &n, &m);

	for(int i = 1; i <= m; ++i) {
		int u, v;
		scanf("%d%d", &u, &v);
		A[i] = u;
		B[i] = v;
		G[u].EB(MP(v, i));
		G[v].EB(MP(u, i));
	}
	
	memset(DEP, -1, sizeof(DEP));
	for(int i = 1; i <= n; ++i) 
		if(DEP[i] == -1) {
			DEP[i] = 0;
			dfs(i, 0);
		}
	
	for(int i = 1; i <= m; ++i) {
		A[i] = _find(A[i]);
		B[i] = _find(B[i]);
		if(A[i] != B[i]) {
			T[A[i]].EB(MP(B[i], i));
			T[B[i]].EB(MP(A[i], i));
		}
	}
	
	scanf("%d", &q);

	for(int i = 0; i < q; ++i) {
		int u, v;
		scanf("%d%d", &u, &v); 
		u = _find(u);
		v = _find(v); 
		++Q[u];
		--Q[v];
	}

	memset(DEP, -1, sizeof(DEP));
	for(int i = 1; i <= n; ++i) 
		if(DEP[_find(i)] == -1) {
			DEP[_find(i)] = 0;
			solve(i, 0);
		}

	for(int i = 1; i <= m; ++i) printf("%c", ANS[i] == -1 ? 'B' : (ANS[i] ? 'R' : 'L'));
	printf("\n");
	return 0;
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:82:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |  scanf("%d%d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:86:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |   scanf("%d%d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:109:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |  scanf("%d", &q);
      |  ~~~~~^~~~~~~~~~
oneway.cpp:113:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  113 |   scanf("%d%d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 7512 KB Output is correct
2 Correct 1 ms 7516 KB Output is correct
3 Correct 2 ms 7516 KB Output is correct
4 Correct 2 ms 7512 KB Output is correct
5 Correct 2 ms 7516 KB Output is correct
6 Correct 2 ms 7516 KB Output is correct
7 Correct 2 ms 7516 KB Output is correct
8 Correct 2 ms 7516 KB Output is correct
9 Correct 2 ms 7516 KB Output is correct
10 Correct 2 ms 7516 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 7512 KB Output is correct
2 Correct 1 ms 7516 KB Output is correct
3 Correct 2 ms 7516 KB Output is correct
4 Correct 2 ms 7512 KB Output is correct
5 Correct 2 ms 7516 KB Output is correct
6 Correct 2 ms 7516 KB Output is correct
7 Correct 2 ms 7516 KB Output is correct
8 Correct 2 ms 7516 KB Output is correct
9 Correct 2 ms 7516 KB Output is correct
10 Correct 2 ms 7516 KB Output is correct
11 Correct 32 ms 12952 KB Output is correct
12 Correct 34 ms 13628 KB Output is correct
13 Correct 34 ms 14420 KB Output is correct
14 Correct 41 ms 15452 KB Output is correct
15 Correct 48 ms 15916 KB Output is correct
16 Correct 48 ms 16468 KB Output is correct
17 Correct 45 ms 17756 KB Output is correct
18 Correct 47 ms 16380 KB Output is correct
19 Correct 47 ms 19028 KB Output is correct
20 Correct 31 ms 13144 KB Output is correct
21 Correct 38 ms 12780 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 7512 KB Output is correct
2 Correct 1 ms 7516 KB Output is correct
3 Correct 2 ms 7516 KB Output is correct
4 Correct 2 ms 7512 KB Output is correct
5 Correct 2 ms 7516 KB Output is correct
6 Correct 2 ms 7516 KB Output is correct
7 Correct 2 ms 7516 KB Output is correct
8 Correct 2 ms 7516 KB Output is correct
9 Correct 2 ms 7516 KB Output is correct
10 Correct 2 ms 7516 KB Output is correct
11 Correct 32 ms 12952 KB Output is correct
12 Correct 34 ms 13628 KB Output is correct
13 Correct 34 ms 14420 KB Output is correct
14 Correct 41 ms 15452 KB Output is correct
15 Correct 48 ms 15916 KB Output is correct
16 Correct 48 ms 16468 KB Output is correct
17 Correct 45 ms 17756 KB Output is correct
18 Correct 47 ms 16380 KB Output is correct
19 Correct 47 ms 19028 KB Output is correct
20 Correct 31 ms 13144 KB Output is correct
21 Correct 38 ms 12780 KB Output is correct
22 Correct 62 ms 19060 KB Output is correct
23 Correct 67 ms 17488 KB Output is correct
24 Correct 57 ms 17704 KB Output is correct
25 Correct 59 ms 21756 KB Output is correct
26 Correct 61 ms 18516 KB Output is correct
27 Correct 57 ms 17488 KB Output is correct
28 Correct 28 ms 11112 KB Output is correct
29 Correct 44 ms 13796 KB Output is correct
30 Correct 47 ms 13784 KB Output is correct
31 Correct 44 ms 14140 KB Output is correct
32 Correct 55 ms 16864 KB Output is correct