10305 - Ordering Tasks.cpp

#include<bits/stdc++.h>
using namespace std;

vector<int>v[105];
vector<int>t;
bool visited[105];


void topsort(int x){

    visited[x]=true;
    for(int i=0;i<v[x].size();i++){
        int xx = v[x][i];
        if(visited[xx]==false) topsort(xx);
    }

    t.push_back(x);
}


int main(){

    int n,e;

    while(cin>>n>>e , !(n==0 && e==0)){

        memset(visited,false,sizeof(visited));
        t.clear();
        for(int i=0;i<100;i++)
            v[i].clear();

        for(int i=0;i<e;i++){
            int a,b;
            cin>>a>>b;
            v[a].push_back(b);
        }

        for(int i=1;i<=n;i++){
            if(visited[i]==false) topsort(i);
        }

        int a = t.size();
        for(int i=a-1;i>=0;i--){
            cout<<t[i];
            if(i!=0) cout<<" ";
        }
        cout<<"\n";


    }

    return 0;

}

/*
5 4
1 2
2 3
1 3
1 5
0 0
*/