C++ implementation of Kahn's algorithm

Kahn's algo(Toposort in DAG).cpp

@@ -0,0 +1,72 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define ld long double
+#define pb push_back
+#define pf push_front
+#define mp make_pair
+#define F first
+#define S second
+#define mod 1000000007
+#define INF INT_MAX
+#define vl vector<ll>
+#define vi vector<int>
+#define pi pair<int,int>
+#define pl pair<ll,ll>
+#define vpl vector<pl>
+#define vpi vector<pi>
+#define ml map<ll,ll>
+#define mi map<int,int>
+#define m(a,b) map<a,b>
+#define YesNo(f) if(f){cout<<"YES"<<endl;}else{cout<<"NO"<<endl;continue;}
+#define setval(a,val) memset(a,val,sizeof(a)) 
+#define fastIO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
+//    1 based node numbering 
+
+const int mxN=200005;
+int in[mxN];
+vi adj[mxN];
+vi sorted;   // for storing the toposort
+bool topoSort(int n){
+	// use priority queue for the smallest sort
+	queue<int> q;
+	for(int i=1;i<=n;i++){
+		if(in[i]==0){
+			q.push(i);
+		}
+	}
+	while(!q.empty()){
+		int node=q.front();
+		q.pop();
+		sorted.pb(node);
+		for(auto i: adj[node]){
+			in[i]--;
+			if(in[i]==0){
+				q.push(i);
+			}
+		}
+	}
+	// checking if the sort is valid, i.e. if the graph contains cycle 
+	// all the nodes will not be present in the final sort
+	return sorted.size()==n;
+}
+
+int main()
+{
+	fastIO;
+//	freopen("input.txt","r",stdin);
+//	freopen("output.txt","w",stdout);
+	int t=1;
+	// cin>>t;
+	while(t--){
+		int n,m,x,y;
+		cin>>n>>m;
+		for(int j=0;j<m;j++){
+			cin>>x>>y;
+			adj[x].pb(y);
+			in[y]++;
+		}
+	}
+
+return 0;
+}