Add doctests to dijkstra_2.py

Author: lorduke22

graphs/dijkstra_2.py

@@ -1,14 +1,47 @@
 def print_dist(dist, v):
+    """
+    Print vertex distance
+
+    Examples:
+    >>> print_dist([float('inf'),float('inf'),float('inf')], 3)
+    <BLANKLINE>
+    Vertex Distance
+    0   INF
+    1   INF
+    2   INF
+    >>> print_dist([2.0,6.0,10.0,3.0], 4)
+    <BLANKLINE>
+    Vertex Distance
+    0   2
+    1   6
+    2   10
+    3   3
+    >>> print_dist([], 4)
+    Traceback (most recent call last):
+     ...
+    IndexError: list index out of range
+    """
     print("\nVertex Distance")
     for i in range(v):
         if dist[i] != float("inf"):
-            print(i, "\t", int(dist[i]), end="\t")
+            print(i, " ", int(dist[i]), end="")
         else:
-            print(i, "\t", "INF", end="\t")
+            print(i, " ", "INF", end="")
         print()
 
 
 def min_dist(mdist, vset, v):
+    """
+    Finds the index of the node with the minimum distance between no-visited nodes
+
+    Examples:
+    >>> dist = [0.0, float('inf'), float('inf'), float('inf')]
+    >>> set = [False, False, False, False]
+    >>> min_dist(dist, set, 4)
+    0
+    >>> min_dist([], [], 0)
+    -1
+    """
     min_val = float("inf")
     min_ind = -1
     for i in range(v):
@@ -19,6 +52,30 @@ def min_dist(mdist, vset, v):
 
 
 def dijkstra(graph, v, src):
+    """
+    Dijkstra's algorithm to calculate the shortest distances from the src source node
+    to all other nodes in a graph represented as an adjacency matrix.
+
+    Examples:
+    >>> G1 = [[0.0, 6.0, 2.0, float('inf')],
+    ... [float('inf'), 0.0, 9.0, 1.0],
+    ... [float('inf'), float('inf'), 0.0, 3.0],
+    ... [float('inf'), float('inf'), float('inf'), 0.0]]
+    >>> dijkstra(G1, 4, 5)
+    Traceback (most recent call last):
+    ...
+    IndexError: list assignment index out of range
+    >>> G2 = [[0.0, 6.0, 2.0, float('inf')],
+    ... [float('inf'), 0.0, 9.0, 1.0],
+    ... [float('inf'), float('inf'), 0.0, 3.0],
+    ... [float('inf'), float('inf'), float('inf'), 0.0]]
+    >>> dijkstra(G2, 4, 0)
+    <BLANKLINE>
+    Vertex Distance
+    0   0
+    1   6
+    2   2
+    """
     mdist = [float("inf") for _ in range(v)]
     vset = [False for _ in range(v)]
     mdist[src] = 0.0
@@ -39,6 +96,10 @@ def dijkstra(graph, v, src):
 
 
 if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod(verbose=True)
+
     V = int(input("Enter number of vertices: ").strip())
     E = int(input("Enter number of edges: ").strip())