Traversal algorithms in graph (DSA in python)

Coding/C++/Pre-computation.cpp

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+// https://codeforces.com/problemset/problem/1807/D
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main(){
+    int t;
+    cin>>t;
+    while(t--){
+        int n,q;
+        cin>>n>>q;
+        long long int a[n];
+        long long int sum=0;
+        for(int i=0;i<n;i++){
+            cin>>a[i];
+
+        }
+        long long int pf[n+1];
+        pf[0]=0;
+        for(int i=1;i<=n;i++){
+            pf[i]=a[i-1]+pf[i-1];
+        }
+
+        for(int i=0;i<q;i++){
+            long long int l,r,k;
+            cin>>l>>r>>k;
+            long long int e=pf[n]-(pf[r]-pf[l-1])+k*(r-l+1);
+
+
+            if(e%2!=0){
+                cout<<"YES"<<endl;
+            }else{
+                cout<<"NO"<<endl;
+            }
+        }
+
+    }
+
+
+
+    return 0;
+}

Coding/Python/BFS and DFS in graph.py

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+#  A program to implement traversal algorithms (BFS and DFS) in the Graph.
+class Graph:
+    def __init__(self):
+        self.graph = {}
+    def addEdge(self, u, v):
+        if u not in self.graph:
+            self.graph[u] = []
+        self.graph[u].append(v)
+    def BFS(self, start):
+        visited = set()
+        queue = [start]
+        bfs_output = []
+        while queue:
+            vertex = queue.pop(0)
+            if vertex not in visited:
+                bfs_output.append(vertex)
+                visited.add(vertex)
+                queue.extend(self.graph.get(vertex, []))
+        return bfs_output
+    def DFS(self, start, visited=None):
+        if visited is None:
+            visited = set()
+        if start not in visited:
+            visited.add(start)
+            for neighbor in self.graph.get(start, []):
+                self.DFS(neighbor, visited)
+        return visited
+if __name__ == '__main__':
+    g = Graph()
+    n = int(input("Enter number of edges: "))
+    for i in range(n):
+        u, v = map(str, input("Enter edge (u v): ").split())
+        g.addEdge(u, v)
+    print("1. BFS")
+    print("2. DFS")
+    choice = int(input("Choose traversal algorithm: "))
+    start_node = input("Enter starting node: ")
+    if choice == 1:
+        print("BFS Traversal:", g.BFS(start_node))
+    else:
+        print("DFS Traversal:", list(g.DFS(start_node)))