Added topological sorting algorithm in C++

topo sort.cp

@@ -0,0 +1,85 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define sz(a) int((a).size())
+#define ll long long
+#define pb push_back
+#define ld long double
+#define mp make_pair
+#define vi vector<ll>
+#define endl "\n"
+#define all(c) (c).begin(),(c).end()
+#define allr(c) (c).rbegin(),(c).rend()
+#define rep(i,n) for(ll i=0;i<n;i++)
+#define cpresent(c,x) (find(all(c),x) != (c).end())
+#define input(a,n) for(long long i=0;i<n;i++)cin>>a[i]
+#define output(a,n) for(long long i=0;i<n;i++)cout<<a[i]<<" "
+#define     she_taught_me_to_code cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(false);cin.tie(NULL);
+#define ep 1e-10
+#define pi pair<ll,ll>
+#define inf 10e9
+#define N 1000000
+bool sortbysec(const pair<int,int> &a,const pair<int,int> &b)
+{
+    return (a.second < b.second);
+}
+ll min(ll a,ll b)
+{
+    if(a<b)
+        return a;
+    return b;
+}
+ll max(ll a,ll b)
+{
+    if(a>b)
+        return a;
+    return b;
+}
+stack<ll> s;
+#define N 1000000
+vector<ll> adj[N];
+vector<bool> visited(N,0);
+void DFSUtil(ll u)
+{
+    visited[u] = true;
+    for (ll i=0; i<adj[u].size(); i++)
+    {
+        if (visited[adj[u][i]] == false)
+        {
+            DFSUtil(adj[u][i]);
+        }
+    }
+    s.push(u);
+}
+void DFS(ll n)
+{
+    for (ll u=1; u<=n; u++)
+    {
+        if (visited[u] == false)
+        {
+            DFSUtil(u);
+        }
+    }
+}
+void aE(ll u, ll v)
+{
+    adj[u].push_back(v);
+}
+int main()
+{
+
+    ll n,m;
+    cin>>n>>m;
+    for(ll i=0;i<m;i++)
+    {
+        ll a,b;
+        cin>>a>>b;
+        aE(a,b);
+    }
+    DFS(n);
+    while(s.empty()==0)
+    {
+        cout<<s.top()<<endl;
+        s.pop();
+    }
+
+}