Cod sursa(job #2237793)

Utilizator radu.leonardoThe Doctor radu.leonardo Data 3 septembrie 2018 04:16:06
Problema Sortare topologica Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.62 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

class Reader {
  public:
    Reader() {}
    Reader(const char *file_name) {
        input_file = fopen(file_name, "r");
        cursor = 0;
        fread(buffer, SIZE, 1, input_file);
    }
    inline Reader &operator >>(int &n) {
        while(buffer[cursor] < '0' || buffer[cursor] > '9') {
            advance();
        }
        n = 0;
        while('0' <= buffer[cursor] && buffer[cursor] <= '9') {
            n = n * 10 + buffer[cursor] - '0';
            advance();
        }
        return *this;
    }
  private:
    FILE *input_file;
    static const int SIZE = 1 << 17;
    int cursor;
    char buffer[SIZE];
    inline void advance() {
        ++ cursor;
        if(cursor == SIZE) {
            cursor = 0;
            fread(buffer, SIZE, 1, input_file);
        }
    }
};

int n,m;
vector<vector<int>> adj(50001);
vector<int> incomingEdges(50001);
vector<int> sorted;
queue<int> q;

int main() {
    Reader fin("sortaret.in");
    ofstream fout("sortaret.out");

    fin>>n>>m;
    for(int i=1; i<=m; i++) {
        int src,dest;
        fin>>src>>dest;
        adj[src].push_back(dest);
        incomingEdges[dest]++;
    }

    for(int i=1; i<=n; i++)
        if(incomingEdges[i]==0)
            q.push(i);

    while(!q.empty()) {
        int current=q.front();
        q.pop();
        sorted.push_back(current);
        for(auto next:adj[current])
            if(--incomingEdges[next]==0)
                q.push(next);
    }

    for(auto it:sorted)
        fout<<it<<' ';

    return 0;
}