Minimax Algorithm

backtracking/minimax.py

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+import math 
+
+''' Minimax helps to achieve maximum score in a game by checking all possible moves
+    depth is current depth in game tree. 
+    nodeIndex is index of current node in scores[].
+    if move is of maximizer return true else false
+    leaves of game tree is stored in scores[]  
+    height is maximum height of Game tree
+'''
+
+def minimax (Depth, nodeIndex, isMax, scores, height):  
+
+    if Depth == height:  
+        return scores[nodeIndex] 
+
+    if isMax: 
+        return (max(minimax(Depth + 1, nodeIndex * 2, False, scores, height),
+                    minimax(Depth + 1, nodeIndex * 2 + 1, False, scores, height))) 
+    return (min(minimax(Depth + 1, nodeIndex * 2, True, scores, height), 
+               minimax(Depth + 1, nodeIndex * 2 + 1, True, scores, height))) 
+
+if __name__ == "__main__": 
+
+    scores = [90, 23, 6, 33, 21, 65, 123, 34423] 
+    height = math.log(len(scores), 2) 
+
+    print("Optimal value : ", end = "") 
+    print(minimax(0, 0, True, scores, height))