this can be easily done using with bfs but if some one wants to try with dfs.

there is two imp point

1 sort all adjacency list in descending order.

2 when apply calling of dfs function iterate vertes in descending order.

*this cause to push vertex with large value first in stack and then with less index vertex.*

```
#include <bits/stdc++.h>
using namespace std;
vector<int> t;
int visit[10000] = {0};
void dfs(vector<int> adj[],int n)
{// {cout<<n<<" ";
if(visit[n]==0)
{visit[n]=1;
for(int i=0;i<adj[n].size();i++)
{
dfs(adj,adj[n][i]);
}
t.push_back(n);
}
}
int main()
{
int n;
cin>>n;
vector<int> adj[n+1];
int m;
cin>>m;
int x,y;
for(int i=0;i<m;i++)
{
cin>>x>>y;
adj[x].push_back(y);
}
for(int i=0;i<=n;i++)
{
sort(adj[i].begin(),adj[i].end(),greater<int>());
}
for(int j=n;j>=1;j--)
{
if(visit[j]==0)
{dfs(adj,j);}
}
for(int j=t.size()-1;j>=0;j--)
{
cout<<t[j]<<" ";
}
return 0;
}
```