Cod sursa(job #2227014)

Utilizator inquisitorAnders inquisitor Data 30 iulie 2018 21:44:45
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.04 kb
#include <stdio.h>
#include <string.h>
#pragma GCC optimize("O1")

int edge[1000010];

int degree[100010];

char level[100010];

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

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

    level[start] = 0;

    Q[qEnd++] = start;

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

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

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

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

char buffer[12500000]; int p;

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

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

    ++p;

    return number;
}

__attribute__((always_inline)) void pass_int()
{
    for(; buffer[p] > 47; ++p);

    ++p;
}

__attribute__((always_inline)) void put_int(int x)
{
    if(x > 9)
    {
        buffer[++p] = x / 10 + 48;

        buffer[++p] = x % 10 + 48;

        buffer[++p] = 32;

        return;
    }

    if(x != -1)
    {
        buffer[++p] = x + 48;

        buffer[++p] = 32;

        return;
    }

    buffer[++p] = 45;

    buffer[++p] = 49;

    buffer[++p] = 32;
}

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

    fread(buffer, 1, 12500000, stdin);

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

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

        pass_int();
    }

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

    degree[0] = M;

    p = 0; pass_int(); pass_int(); pass_int();

    for(int i = M + 1; --i;)
    {
        edge[--degree[get_int()]] = get_int();
    }

    BFS(start);

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

    p = -1;

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

    fwrite(buffer, 1, p, stdout);

    return 0;
}