oj.uz

Submission #67537

# Submission time Handle Problem Language Result Execution time Memory
67537 2018-08-14T18:42:36 Z MiricaMatei One-Way Streets (CEOI17_oneway) C++14
100 / 100
 798 ms 55052 KB 
#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 100000;

struct Edge {
  int a, b;
  int other(int node) {
    return a ^ b ^ node;
  }
}e[MAX_N + 5];

vector<int>G[MAX_N + 5];
int h[MAX_N + 5], low[MAX_N + 5];
bool viz[MAX_N + 5];

int t1[MAX_N + 5], h1[MAX_N + 5];
int indcomp[MAX_N + 5];
vector<int>comp[MAX_N + 5];

vector<int>G1[MAX_N + 5];
int t2[MAX_N + 5], h2[MAX_N + 5];
int niv[MAX_N + 5], f[MAX_N + 5];
int mp[MAX_N + 5], nd[MAX_N + 5];

char sol[MAX_N + 5];

int f1(int x) {
  int y = x;
  while (x != t1[x])
    x = t1[x];
  while (y != t1[y]) {
    int aux = t1[y];
    t1[y] = x;
    y = aux;
  }
  return x;
}

void u1(int x, int y) {
  x = f1(x);
  y = f1(y);
  if (x == y)
    return ;
  if (h1[y] > h1[x])
    swap(x, y);
  t1[y] = x;
  if (h1[x] == h1[y])
    h1[x]++;
}

void dfs(int nod, int ff) {
  viz[nod] = 1;
  for (auto it:G[nod]) {
    int v = e[it].other(nod);
    if (!viz[v]) {
      low[v] = h[v] = h[nod] + 1;
      dfs(v, it);
      low[nod] = min(low[nod], low[v]);
      if (low[v] <= h[nod])
        u1(nod, v);
    } else if (it != ff) {
      low[nod] = min(low[nod], h[v]);
    }
  }
}

void solve1(int nod, int ff) {
  viz[nod] = 1;
  for (auto it:G[nod])
    if (it != ff) {
      int v = e[it].other(nod);
      if (indcomp[nod] == indcomp[v]) {
        sol[it] = 'B';
        if (!viz[v])
          solve1(v, it);
      }
    }
}

int other(int it, int nod) {
  if (indcomp[e[it].a] == nod)
    return e[it].b;
  return e[it].a;
}

void dfs2(int nod, int ff) {
  viz[nod] = 1;
  for (auto it:G1[nod]) {
    int v = indcomp[other(it, nod)];
    if (v != ff) {
      niv[v] = 1 + niv[nod];
      f[v] = nod;
      mp[v] = it;
      dfs2(v, nod);
    }
  }
}

int f2(int x) {
  int y = x;
  while (t2[x] != x)
    x = t2[x];
  while (y != t2[y]) {
    int aux = t2[y];
    t2[y] = x;
    niv[y] = niv[x];
    nd[y] = nd[x];
    y = aux;
  }
  return x;
}

void u2(int x, int y) {
  x = f2(x);
  y = f2(y);
  if (x == y)
    return ;
  if (h[y] > h[x])
    swap(x, y);
  t2[y] = x;
  if (h2[x] == h2[y])
    h2[x]++;
  if (niv[y] < niv[x]) {
    niv[x] = niv[y];
    nd[x] = nd[y];
  }
}

void solve2(int a, int b) {
  if (sol[mp[a]])
    a = nd[f2(a)];
  if (sol[mp[b]])
    b = nd[f2(b)];
  while (a != b) {
    if (niv[a] > niv[b]) {
      int aux = f[a];
      if (indcomp[e[mp[a]].a] == a)
        sol[mp[a]] = 'R';
      else
        sol[mp[a]] = 'L';
      u2(aux, a);
      if (sol[mp[f[a]]]) {
        u2(a, f[a]);
        a = nd[f2(a)];
      } else {
        a = aux;
      }
    } else {
      int aux = f[b];
      if (indcomp[e[mp[b]].a] == b)
        sol[mp[b]] = 'L';
      else
        sol[mp[b]] = 'R';
      u2(aux, b);
      if (sol[mp[f[b]]]) {
        u2(b, f[b]);
        b = nd[f2(b)];
      } else {
        b = aux;
      }
    }
  }
}

int main() {
  //freopen("date.in", "r", stdin);
  //freopen("date.out", "w", stdout);

  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= m; ++i) {
    int x, y;
    scanf("%d%d", &x, &y);
    e[i] = {x, y};
    G[x].push_back(i);
    G[y].push_back(i);
  }

  for (int i = 1; i <= n; ++i)
    t1[i] = t2[i] = nd[i] = i;

  for (int i = 1; i <= n; ++i)
    if (!viz[i])
      dfs(i, 0);

  for (int i = 1; i <= n; ++i) {
    int aux = f1(i);
    indcomp[i] = aux;
    comp[aux].push_back(i);
  }

  for (int i = 1; i <= n; ++i)
    if ((int)comp[i].size() > 0) {
      memset(viz, 0, sizeof(viz));
      solve1(comp[i][0], 0);
    }

  for (int i = 1; i <= m; ++i)
    if (indcomp[e[i].a] != indcomp[e[i].b]) {
      G1[indcomp[e[i].a]].push_back(i);
      G1[indcomp[e[i].b]].push_back(i);
    }

  memset(viz, 0, sizeof(viz));
  for (int i = 1; i <= n; ++i)
    if (!viz[indcomp[i]])
      dfs2(indcomp[i], 0);

  int p;
  scanf("%d", &p);
  for (int i = 1; i <= p; ++i) {
    int x, y;
    scanf("%d%d", &x, &y);
    if (indcomp[x] != indcomp[y])
      solve2(indcomp[x], indcomp[y]);
  }

  for (int i = 1; i <= m; ++i) {
    if (!sol[i])
      sol[i] = 'B';
    printf("%c", sol[i]);
  }

  return 0;
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:172:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &n, &m);
   ~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:175:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &x, &y);
     ~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:212:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &p);
   ~~~~~^~~~~~~~~~
oneway.cpp:215:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &x, &y);
     ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 7544 KB Output is correct
2 Correct 9 ms 7616 KB Output is correct
3 Correct 11 ms 7724 KB Output is correct
4 Correct 18 ms 7756 KB Output is correct
5 Correct 16 ms 7908 KB Output is correct
6 Correct 9 ms 7908 KB Output is correct
7 Correct 16 ms 7908 KB Output is correct
8 Correct 15 ms 7908 KB Output is correct
9 Correct 9 ms 7964 KB Output is correct
10 Correct 11 ms 7980 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 7544 KB Output is correct
2 Correct 9 ms 7616 KB Output is correct
3 Correct 11 ms 7724 KB Output is correct
4 Correct 18 ms 7756 KB Output is correct
5 Correct 16 ms 7908 KB Output is correct
6 Correct 9 ms 7908 KB Output is correct
7 Correct 16 ms 7908 KB Output is correct
8 Correct 15 ms 7908 KB Output is correct
9 Correct 9 ms 7964 KB Output is correct
10 Correct 11 ms 7980 KB Output is correct
11 Correct 86 ms 13428 KB Output is correct
12 Correct 88 ms 16036 KB Output is correct
13 Correct 156 ms 18928 KB Output is correct
14 Correct 307 ms 23120 KB Output is correct
15 Correct 443 ms 25564 KB Output is correct
16 Correct 660 ms 28904 KB Output is correct
17 Correct 657 ms 31628 KB Output is correct
18 Correct 704 ms 31628 KB Output is correct
19 Correct 692 ms 35088 KB Output is correct
20 Correct 107 ms 35088 KB Output is correct
21 Correct 101 ms 35088 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 7544 KB Output is correct
2 Correct 9 ms 7616 KB Output is correct
3 Correct 11 ms 7724 KB Output is correct
4 Correct 18 ms 7756 KB Output is correct
5 Correct 16 ms 7908 KB Output is correct
6 Correct 9 ms 7908 KB Output is correct
7 Correct 16 ms 7908 KB Output is correct
8 Correct 15 ms 7908 KB Output is correct
9 Correct 9 ms 7964 KB Output is correct
10 Correct 11 ms 7980 KB Output is correct
11 Correct 86 ms 13428 KB Output is correct
12 Correct 88 ms 16036 KB Output is correct
13 Correct 156 ms 18928 KB Output is correct
14 Correct 307 ms 23120 KB Output is correct
15 Correct 443 ms 25564 KB Output is correct
16 Correct 660 ms 28904 KB Output is correct
17 Correct 657 ms 31628 KB Output is correct
18 Correct 704 ms 31628 KB Output is correct
19 Correct 692 ms 35088 KB Output is correct
20 Correct 107 ms 35088 KB Output is correct
21 Correct 101 ms 35088 KB Output is correct
22 Correct 763 ms 38668 KB Output is correct
23 Correct 719 ms 39404 KB Output is correct
24 Correct 798 ms 41808 KB Output is correct
25 Correct 754 ms 48636 KB Output is correct
26 Correct 760 ms 48636 KB Output is correct
27 Correct 768 ms 48908 KB Output is correct
28 Correct 76 ms 48908 KB Output is correct
29 Correct 136 ms 48908 KB Output is correct
30 Correct 127 ms 48908 KB Output is correct
31 Correct 116 ms 48908 KB Output is correct
32 Correct 295 ms 55052 KB Output is correct