Add kattis prob breakingbad in python3 + notes

kattis/breakingbad/notes.md

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+The problem asks to figure out if the given graph is bipartite. A graph colouring solution works, marking nodes the opposite colour to all that they are connected with, and then seeing if you try to colour a node two different colours. If so, the graph is not bipartite.

kattis/breakingbad/solution.py

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+from collections import deque
+
+def main():
+    n = int(input())
+    words = [input() for _ in range(n)]
+    word_to_int = {words[i]:i for i in range(n)}
+    edges = [[] for _ in range(n)]
+    #edges = {w:[] for w in words}
+
+    m = int(input())
+    for _ in range(m):
+        a, b = input().split()
+        i = word_to_int[a]
+        j = word_to_int[b]
+        edges[i].append(j)
+        edges[j].append(i)
+
+    colours = {}
+    q = deque()
+    qapp = q.append
+    for start in range(n):
+        if start in colours:
+            continue
+        qapp((start, True))
+        while len(q):
+            curr, colour = q.pop()
+            if curr in colours and colours[curr] != colour:
+                print('impossible')
+                return
+            colours[curr] = colour
+            c = not colour
+            for o in edges[curr]:
+                if o in colours:
+                    if colours[o] != c:
+                        print('impossible')
+                        return
+                else:
+                    qapp((o, c))
+    ans = [[], []]
+    for k in colours:
+        ans[int(colours[k])].append(words[k])
+    print(*ans[0])
+    print(*ans[1])
+
+
+if __name__ == '__main__':
+    main()