Cod sursa(job #2134648)

Utilizator Kln1000Ciobanu Bogdan Kln1000 Data 18 februarie 2018 10:58:12
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 3.24 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
#include <cstring>

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;

#define INF 0x8000

class parser{
    public:
        parser() {}
        parser(const char *file_name){
            input_file.open(file_name,ios::in | ios::binary);
            input_file.sync_with_stdio(false);
            index&=0;
            input_file.read(buffer,SIZE);}
        inline parser &operator >>(int &n){
            for (;buffer[index]<'0' or buffer[index]>'9';inc());
            n&=0;
            //sign&=0;
            //sign|=(buffer[index-1]=='-');
            for (;'0'<=buffer[index] and buffer[index]<='9';inc())
                n=(n<<1)+(n<<3)+buffer[index]-'0';
            //n^=((n^-n)&-sign);
            return *this;}
        ~parser(){
            input_file.close();}
    private:
        fstream input_file;
        static const int SIZE=0x400000; ///4MB
        char buffer[SIZE];
        int index/*,sign*/;
        inline void inc(){
            if(++index==SIZE)
                index=0,input_file.read(buffer,SIZE);}
};

class writer{
    public:
        writer() {};
        writer(const char *file_name){
            output_file.open(file_name,ios::out | ios::binary);
            output_file.sync_with_stdio(false);
            index&=0;}
        inline writer &operator <<(int target){
            aux&=0;
            sign&=0;
            n=target;
            if (n<0)
                sign=1,
                buffer[index]='-',
                inc();
            n^=((n^-n)&-sign);
            if (!n)
                nr[aux++]='0';
            for (;n;n/=10)
                nr[aux++]=n%10+'0';
            for(;aux;inc())
                buffer[index]=nr[--aux];
            return *this;}
        inline writer &operator <<(const char *target){
            aux&=0;
            while (target[aux])
                buffer[index]=target[aux++],inc();
            return *this;}
        ~writer(){
            output_file.write(buffer,index);output_file.close();}
    private:
        fstream output_file;
        static const int SIZE=0x200000; ///2MB
        int index,aux,n,sign;
        char buffer[SIZE],nr[24];
        inline void inc(){
            if(++index==SIZE)
                index&=0,output_file.write(buffer,SIZE);}
};

parser f ("bfs.in");
writer t ("bfs.out");

vector <int> v[100010];
bitset <100010> in_queue;
int dist[100010];

void bfs(int start){
    queue <int> q;
    q.push(start);
    in_queue[start]=true;
    dist[start]&=0;
    while(!q.empty()){
        int nod=q.front();
        in_queue[nod]=false,
        q.pop();
        for (auto i:v[nod])
            if (dist[i]>1+dist[nod] or dist[i]==-1){
                dist[i]=1+dist[nod];
                if (!in_queue[i])
                    q.push(i);
            }
    }
}

int main()
{
    int n,m,s;
    f>>n>>m>>s;
    for (int x,y,i=0;i<m;++i)
        f>>x>>y,
        v[x].push_back(y);
    memset(dist,-1,sizeof(dist));
    bfs(s);
    for (int i=1;i<=n;++i)
        t<<(dist[i]==INF?-1:dist[i])<<" ";
    return 0;
}