Cod sursa(job #2226424)

Utilizator inquisitorAnders inquisitor Data 30 iulie 2018 10:51:29
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.08 kb
///not written by me. im just having some fun
#include <bits/stdc++.h>
using namespace std;

const int MAXBUF = 12500000;
char parseBuf[MAXBUF];
char *head;
bool isDigit[255];
char *writeHead;

void parseInit() {
  int a = fread(parseBuf, 1, MAXBUF, stdin);
  parseBuf[a] = 0;

  head = parseBuf;

  for (int i = '0'; i <= '9'; ++i)
    isDigit[i] = true;

  writeHead = head;
}

__attribute__((always_inline)) int nextInt() {
  int ans = 0;
  for (; !isDigit[*head]; ++head);
  for (; isDigit[*head]; ++head)
    ans = ans * 10 + (*head) - '0';
  return ans;
}

const int MAXN = 100010;
const int MAXM = 1000010;
int muchii[MAXM];
int offsetOf[MAXN];
char dst[MAXN];
int Q[MAXN], qs, qe;

void BFS(int s) {
  memset(dst, 0xFF, sizeof dst);
  qs = qe = 0;
  dst[s] = 0;
  Q[qe++] = s;
  while (qs < qe) {
     int t = Q[qs++];
    for ( int it = offsetOf[t], tar = offsetOf[t + 1]; it != tar; ++it) {
       int v = muchii[it];
      if (dst[v] >= 0)
        continue;
      dst[v] = dst[t] + 1;
      Q[qe++] = v;
    }
  }
}

__attribute__((always_inline)) void putNumber(int x) {
  if (x == 0) {
    *(writeHead++) = '0';
    *(writeHead++) = ' ';
    return;
  }
  if (x < 0) {
    *(writeHead++) = '-';
    *(writeHead++) = '1';
    *(writeHead++) = ' ';
    return;
  }
  char *old = writeHead;
  while (x) {
    *(writeHead++) = x % 10 + '0';
    x /= 10;
  }
  reverse(old, writeHead);
  *(writeHead++) = ' ';
}

int main() {
  freopen("bfs.in", "r", stdin);
  freopen("bfs.out", "w", stdout);
  parseInit();
  int N = nextInt(), M = nextInt(), S = nextInt();
  for ( int i = 0; i < M; ++i) {
    ++offsetOf[nextInt()];
    nextInt();
  }
  for ( int i = 1; i <= N; ++i)
    offsetOf[i] += offsetOf[i - 1];
  offsetOf[N + 1] = M;
  head = parseBuf;
  nextInt(), nextInt(), nextInt();
  for ( int i = 0; i < M; ++i) {
     int a = nextInt(), b = nextInt();
    muchii[--offsetOf[a]] = b;
  }
  BFS(S);
  for ( int i = 1; i <= N; ++i)
    putNumber(dst[i]);
  fwrite(parseBuf, 1, writeHead - parseBuf, stdout);
  return 0;
}