oj.uz

Submission #43123

# Submission time Handle Problem Language Result Execution time Memory
43123 2018-03-09T09:48:20 Z win11905 One-Way Streets (CEOI17_oneway) C++11
100 / 100
 142 ms 20524 KB 
#include <bits/stdc++.h>
#define pii pair<int, int>
#define x first
#define y second
using namespace std;

const int MAXN = 1e5 + 5;

vector<pii> g[MAXN];
int n, m, par[MAXN][18], dep[MAXN], d1[MAXN], d2[MAXN];
char ans[MAXN];
bool chk[MAXN];
pii E[MAXN];

void dfs(int u, int p) {
	dep[u] = dep[p] + 1;
	par[u][0] = p;
	for(int i = 1; i <= 17; ++i) par[u][i] = par[par[u][i-1]][i-1];
	for(auto v : g[u]) if(par[v.x][0] == -1) {
		chk[v.y] = true;
		dfs(v.x, u);
	}
}

int lca(int a, int b) {
	if(dep[a] < dep[b]) swap(a, b);
	for(int i = 17; i >= 0; --i) if(dep[par[a][i]] >= dep[b]) a = par[a][i];
	if(a == b) return a;
	for(int i = 17; i >= 0; --i) if(par[a][i] != par[b][i]) a = par[a][i], b=  par[b][i];
	return par[a][0];
}

void dfs1(int u) {
	for(auto v : g[u]) if(par[v.x][0] == u && chk[v.y]) {
		dfs1(v.x);
		d1[u] += d1[v.x], d2[u] += d2[v.x];
		ans[v.y] = 'B';
		int node = -1;
		if(d2[v.x] > 0) node = v.x;
		if(d2[v.x] < 0) node = u;
		if(node == -1 || d1[v.x]) continue;
		if(node == E[v.y].x) ans[v.y] = 'R';
		else ans[v.y] = 'L';
	}
}

int main() {
	#ifdef INPUT
	freopen("r", "r", stdin);
	#endif
	memset(par, -1, sizeof par);
	scanf("%d %d", &n, &m);
	for(int i = 1; i <= m; ++i) {
		int u, v; scanf("%d %d", &u, &v);
		g[u].emplace_back(v, i);
		g[v].emplace_back(u, i);
		E[i] = pii(u, v);
	}
	for(int i = 1; i <= n; ++i) if(par[i][0] == -1) dfs(i, 0);
	for(int i = 1; i <= m; ++i) if(!chk[i]) d1[E[i].x]++, d1[E[i].y]++, d1[lca(E[i].x, E[i].y)] -= 2, ans[i] = 'B';
	int t; scanf("%d", &t);
	while(t--) {
		int a, b;
		scanf("%d %d", &a, &b);
		d2[a]++, d2[b]--;
	}
	for(int i = 1; i <= n; ++i) if(!par[i][0]) dfs1(i);
	printf("%s\n", ans+1);
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:52:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
                        ^
oneway.cpp:54:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v; scanf("%d %d", &u, &v);
                                   ^
oneway.cpp:61:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  int t; scanf("%d", &t);
                        ^
oneway.cpp:64:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &a, &b);
                         ^

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 9720 KB Output is correct
2 Correct 9 ms 9720 KB Output is correct
3 Correct 9 ms 9876 KB Output is correct
4 Correct 9 ms 9876 KB Output is correct
5 Correct 9 ms 9876 KB Output is correct
6 Correct 9 ms 9932 KB Output is correct
7 Correct 9 ms 9932 KB Output is correct
8 Correct 9 ms 9932 KB Output is correct
9 Correct 9 ms 9932 KB Output is correct
10 Correct 9 ms 9932 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 9720 KB Output is correct
2 Correct 9 ms 9720 KB Output is correct
3 Correct 9 ms 9876 KB Output is correct
4 Correct 9 ms 9876 KB Output is correct
5 Correct 9 ms 9876 KB Output is correct
6 Correct 9 ms 9932 KB Output is correct
7 Correct 9 ms 9932 KB Output is correct
8 Correct 9 ms 9932 KB Output is correct
9 Correct 9 ms 9932 KB Output is correct
10 Correct 9 ms 9932 KB Output is correct
11 Correct 84 ms 15124 KB Output is correct
12 Correct 98 ms 16116 KB Output is correct
13 Correct 117 ms 17228 KB Output is correct
14 Correct 132 ms 17800 KB Output is correct
15 Correct 142 ms 17928 KB Output is correct
16 Correct 115 ms 17928 KB Output is correct
17 Correct 99 ms 17928 KB Output is correct
18 Correct 97 ms 17928 KB Output is correct
19 Correct 99 ms 18712 KB Output is correct
20 Correct 90 ms 18712 KB Output is correct
21 Correct 79 ms 18712 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 9720 KB Output is correct
2 Correct 9 ms 9720 KB Output is correct
3 Correct 9 ms 9876 KB Output is correct
4 Correct 9 ms 9876 KB Output is correct
5 Correct 9 ms 9876 KB Output is correct
6 Correct 9 ms 9932 KB Output is correct
7 Correct 9 ms 9932 KB Output is correct
8 Correct 9 ms 9932 KB Output is correct
9 Correct 9 ms 9932 KB Output is correct
10 Correct 9 ms 9932 KB Output is correct
11 Correct 84 ms 15124 KB Output is correct
12 Correct 98 ms 16116 KB Output is correct
13 Correct 117 ms 17228 KB Output is correct
14 Correct 132 ms 17800 KB Output is correct
15 Correct 142 ms 17928 KB Output is correct
16 Correct 115 ms 17928 KB Output is correct
17 Correct 99 ms 17928 KB Output is correct
18 Correct 97 ms 17928 KB Output is correct
19 Correct 99 ms 18712 KB Output is correct
20 Correct 90 ms 18712 KB Output is correct
21 Correct 79 ms 18712 KB Output is correct
22 Correct 141 ms 18712 KB Output is correct
23 Correct 129 ms 18712 KB Output is correct
24 Correct 138 ms 18712 KB Output is correct
25 Correct 134 ms 20524 KB Output is correct
26 Correct 129 ms 20524 KB Output is correct
27 Correct 132 ms 20524 KB Output is correct
28 Correct 60 ms 20524 KB Output is correct
29 Correct 123 ms 20524 KB Output is correct
30 Correct 112 ms 20524 KB Output is correct
31 Correct 120 ms 20524 KB Output is correct
32 Correct 128 ms 20524 KB Output is correct