Data commit

Task/Monty-Hall-problem/MATLAB/monty-hall-problem-1.m

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+function montyHall(numDoors,numSimulations)
+
+    assert(numDoors > 2);
+
+    function num = randInt(n)
+        num = floor( n*rand()+1 );
+    end
+
+    %The first column will tallie wins, the second losses
+    switchedDoors = [0 0];
+    stayed = [0 0];
+
+
+    for i = (1:numSimulations)
+
+        availableDoors = (1:numDoors); %Preallocate the available doors
+        winningDoor = randInt(numDoors); %Define the winning door
+        playersOriginalChoice = randInt(numDoors); %The player picks his initial choice
+
+        availableDoors(playersOriginalChoice) = []; %Remove the players choice from the available doors
+
+        %Pick the door to open from the available doors
+        openDoor = availableDoors(randperm(numel(availableDoors))); %Sort the available doors randomly
+        openDoor(openDoor == winningDoor) = []; %Make sure Monty doesn't open the winning door
+        openDoor = openDoor(randInt(numel(openDoor))); %Choose a random door to open
+
+        availableDoors(availableDoors==openDoor) = []; %Remove the open door from the available doors
+        availableDoors(end+1) = playersOriginalChoice; %Put the player's original choice back into the pool of available doors
+        availableDoors = sort(availableDoors);
+
+        playersNewChoice = availableDoors(randInt(numel(availableDoors))); %Pick one of the available doors
+
+        if playersNewChoice == playersOriginalChoice
+            switch playersNewChoice == winningDoor
+                case true
+                    stayed(1) = stayed(1) + 1;
+                case false
+                    stayed(2) = stayed(2) + 1;
+                otherwise
+                    error 'ERROR'
+            end
+        else
+            switch playersNewChoice == winningDoor
+                case true
+                    switchedDoors(1) = switchedDoors(1) + 1;
+                case false
+                    switchedDoors(2) = switchedDoors(2) + 1;
+                otherwise
+                    error 'ERROR'
+            end
+        end
+    end
+
+    disp(sprintf('Switch win percentage: %f%%\nStay win percentage: %f%%\n', [switchedDoors(1)/sum(switchedDoors),stayed(1)/sum(stayed)] * 100));
+
+end

Task/Monty-Hall-problem/MATLAB/monty-hall-problem-2.m

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+>> montyHall(3,100000)
+Switch win percentage: 66.705972%
+Stay win percentage: 33.420062%