Cod sursa(job #2196323)

Utilizator mouse_wirelessMouse Wireless mouse_wireless Data 18 aprilie 2018 23:54:58
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.31 kb
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
#define mp make_pair
#define CHECK(x) if(!(x)) return false;
typedef pair<int, int> pii;

#ifdef INFOARENA
#define ProblemName "bfs"
#endif

#define MCONCAT(A, B) A B
#ifdef ProblemName
#define InFile MCONCAT(ProblemName, ".in")
#define OuFile MCONCAT(ProblemName, ".out")
#else
#define InFile "fis.in"
#define OuFile "fis.out"
#endif

const int MAXBUF = 20000000;
char parseBuf[MAXBUF];
char *head;
bool isDigit[255];
char *writeHead;

void parseInit() {
  int a = fread(parseBuf, 1, MAXBUF, stdin);
  parseBuf[a] = 0;
  head = parseBuf;
  memset(isDigit, 0, sizeof isDigit);
  for (int i = '0'; i <= '9'; ++i)
    isDigit[i] = true;
  writeHead = head;
}

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 info[MAXM], nxt[MAXM];
int nextNode = 1;
int dst[MAXN];
bool viz[MAXN];
int G[MAXN];
int Q[MAXN], qs, qe;

inline void setViz(int x) {
  viz[x] = true;
}

inline int isViz(int x) {
  return viz[x];
}

void BFS(int s) {
  memset(dst, 0xFF, sizeof dst);
  qs = qe = 0;
  dst[s] = 0;
  setViz(s);
  Q[qe++] = s;
  while (qs < qe) {
    int t = Q[qs++];
    for (int it = G[t]; it; it = nxt[it]) {
      int v = info[it];
      if (isViz(v))
        continue;
      setViz(v);
      dst[v] = dst[t] + 1;
      Q[qe++] = v;
    }
  }
}

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(InFile, "r", stdin);
  freopen(OuFile, "w", stdout);
  parseInit();
  int N = nextInt(), M = nextInt(), S = nextInt();
  while (M--) {
    int a = nextInt(), b = nextInt();
    info[nextNode] = b;
    nxt[nextNode] = G[a];
    G[a] = nextNode;
    ++nextNode;
  }
  BFS(S);
  for (int i = 1; i <= N; ++i)
    putNumber(dst[i]);
  fwrite(parseBuf, 1, writeHead - parseBuf, stdout);
  return 0;
}