Cod sursa(job #2226780)

Utilizator inquisitorAnders inquisitor Data 30 iulie 2018 16:51:20
Problema BFS - Parcurgere in latime Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 2 kb
#include <stdio.h>
#include <string.h>
#pragma GCC optimize("O1")

unsigned edge[1000010];

unsigned degree[100010];

char level[100010];

void BFS(unsigned start)
{
    memset(level, 0xFF, sizeof level);

    unsigned Q[100010], qStart = 0, qEnd = 0;

    level[start] = 0;

    Q[qEnd++] = start;

    while(qStart < qEnd)
    {
        unsigned u = Q[qStart++];

        for(unsigned it = degree[u], end = degree[u + 1]; it != end; ++it)
        {
            unsigned v = edge[it];

            if(level[v] == -1)
            {
                level[v] = level[u] + 1;

                Q[qEnd++] = v;
            }
        }
    }
}

char buffer[20000000]; unsigned p = -1;

__attribute__((always_inline)) unsigned get_int()
{
    unsigned number = 0;

    for(++p; buffer[p] > 47; ++p)
    {
        number = number * 10 + buffer[p] - 48;
    }

    return number;
}

__attribute__((always_inline)) void put_int(unsigned x)
{
    if(x > 99)
    {
        buffer[++p] = x / 10 + 48;

        buffer[++p] = x % 10 + 48;
    }
    else if(x == -1)
    {
        buffer[++p] = 45;

        buffer[++p] = 49;
    }
    else
    {
        buffer[++p] = x + 48;
    }

    buffer[++p] = 32;
}

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

    fread(buffer, 1, 12500000, stdin);

    unsigned N = get_int(), M = get_int(), start = get_int(), u, v;

    for( unsigned i = M + 1; --i; )
    {
        ++degree[get_int()];

        get_int();
    }

    for( unsigned i = 1; i <= N; ++i)
    {
        degree[i] += degree[i - 1];
    }

    degree[N + 1] = M;

    p = -1; get_int(); get_int(); get_int();

    for( unsigned i = M + 1; --i; )
    {
        u = get_int();

        v = get_int();

        edge[--degree[u]] = v;
    }

    BFS(start);

    freopen("bfs.out", "w", stdout);

    p = -1;

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

    fwrite(buffer, 1, p, stdout);

    return 0;
}