Cod sursa(job #2222352)

Utilizator inquisitorAnders inquisitor Data 16 iulie 2018 21:58:03
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.42 kb
#include <cstdio>
#include <malloc.h>

int q = -1;

char outBuffer[800000];

__attribute__((always_inline)) void put_int(int x)
{
    if(x == -1)
    {
        outBuffer[++q] = 45;

        outBuffer[++q] = 49;

        outBuffer[++q] = 32;

        return;
    }

    int digits = x > 999999999 ? 11 :
                 x > 99999999  ? 10 :
                 x > 9999999   ? 9  :
                 x > 999999    ? 8  :
                 x > 99999     ? 7  :
                 x > 9999      ? 6  :
                 x > 999       ? 5  :
                 x > 99        ? 4  :
                 x > 9         ? 3  : 2;

    for(int i = digits; --i; x /= 10)
    {
        outBuffer[q + i] = x % 10 + 48;
    }

    outBuffer[q = q + digits] = 32;
}

#define IN_BUFFER_SIZE 20000000

char inBuffer[IN_BUFFER_SIZE], *head, isDigit[255];

void initialize_parser()
{
    inBuffer[fread(inBuffer, 1, IN_BUFFER_SIZE, stdin)] = 0;

    head = inBuffer;

    for(int i = 48; i < 58; ++i)
    {
        isDigit[i] = true;
    }
}

int get_int()
{
    int ans = 0;

    for(; !isDigit[*head]; ++head);

    for(; isDigit[*head]; ++head)

        ans = ans * 10 + (*head) - 48;

    return ans;
}

int *Graph[100001], degree[100001], level[100001], u[1000001], v[1000001];

void BFS(int start)
{
    int queue[100001], left = 0, right = 0, *child;

    level[queue[0] = start] = 1;

    for(; left <= right; ++left)
    {
        for(child = Graph[queue[left]] + 1; *child != -1; ++child)
        {
            if(!level[*child])
            {
                queue[++right] = *child;

                level[*child] = level[queue[left]] + 1;
            }
        }
    }
}

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

    initialize_parser();

    int N = get_int(), M = get_int(), start = get_int();

    for(int i = 1; i <= M; i++)
    {
        u[i] = get_int(), v[i] = get_int();

        ++degree[u[i]];
    }

    for(int i = 1; i <= N; ++i)
    {
        Graph[i] = (int*)malloc((degree[i] + 2) * sizeof(int));

        Graph[i][degree[i] + 1] = -1;

        degree[i] = 0;
    }

    for(int i = 1; i <= M; i++)
    {
        Graph[u[i]][++degree[u[i]]] = v[i];
    }

    BFS(start);

    for(int i = 1; i <= N; i++)
    {
        put_int(level[i] - 1);
    }

    fwrite(outBuffer, 1, q, stdout);

    return 0;
}