Added HackerEarth Graph problems

OmkarPathak · OmkarPathak · commit 71f7668e342a · 2017-09-04T07:14:38.000+05:30
diff --git a/CompetitiveProgramming/HackerEarth/Algorithms/Graphs/Monk-At-The-Graph-Factory.py b/CompetitiveProgramming/HackerEarth/Algorithms/Graphs/Monk-At-The-Graph-Factory.py
@@ -0,0 +1,38 @@
+# Our Code Monk recently learnt about Graphs and is very excited!
+#
+# He went over to the Graph-making factory to watch some freshly prepared graphs. Incidentally,
+# one of the workers at the factory was ill today, so Monk decided to step in and do her job.
+#
+# The Monk's Job is to Identify whether the incoming graph is a tree or not. He is given N, the number
+# of vertices in the graph and the degree of each vertex.
+#
+# Find if the graph is a tree or not.
+#
+# Input:
+# First line contains an integer N, the number of vertices.
+# Second line contains N space-separated integers, the degrees of the N vertices.
+#
+# Output:
+# Print "Yes" (without the quotes) if the graph is a tree or "No" (without the quotes) otherwise.
+#
+# Constraints:
+# 1 &le; N &le; 100
+# 1 &le; Degreei &le; 1000
+#
+# SAMPLE INPUT
+# 3
+# 1 2 1
+#
+# SAMPLE OUTPUT
+# Yes
+
+n = int(input())
+degrees = [int(i) for i in input().split()]
+
+# Number of nodes are given thus in a tree number of edges are (n-1) and each edge has two degree
+# thus in tree data structure total degree should be 2*(n-1) and this should be equal to sum of given degree
+
+if(2 * (n - 1) == sum(degrees)):
+    print('Yes')
+else:
+    print('No')
diff --git a/CompetitiveProgramming/HackerEarth/Algorithms/Graphs/Monk-In-The-Real-Estate.py b/CompetitiveProgramming/HackerEarth/Algorithms/Graphs/Monk-In-The-Real-Estate.py
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+# The Monk wants to buy some cities. To buy two cities, he needs to buy the road connecting those two cities. 
+# Now, you are given a list of roads, bought by the Monk. You need to tell how many cities did the Monk buy.
+#
+# Input:
+# First line contains an integer T, denoting the number of test cases. The first line of each test case
+# contains an integer E, denoting the number of roads. The next E lines contain two space separated
+# integers X and Y, denoting that there is an road between city X and city Y.
+#
+# Output:
+# For each test case, you need to print the number of cities the Monk bought.
+#
+# Constraint:
+# 1 <= T <= 100
+# 1 <= E <= 1000
+# 1 <= X, Y <= 10000
+#
+# SAMPLE INPUT
+# 1
+# 3
+# 1 2
+# 2 3
+# 1 3
+
+for _ in range(int(input())):
+    roads = int(input())
+    lst = set([])
+    for i in range(roads):
+        node1,node2 = map(int,input().split())
+        lst.add(node1)
+        lst.add(node2)
+    print(len(lst))
