checkpoint1

03week/towersOfHanoi.js

@@ -1,5 +1,15 @@
 'use strict';
 
+/* Function planning
+function movePiece will move from start stack to end stack 
+function isLegal will test whether the move is legal- will return true or false
+function checkForWin will check each move for a win- will return true or false
+function reset will reset the game is checkForWin is true
+2 new tests - test if the startStack is empty
+            - small block onto larger block
+*/
+
+
 const assert = require('assert');
 const readline = require('readline');
 const rl = readline.createInterface({
@@ -19,24 +29,66 @@ function printStacks() {
   console.log("c: " + stacks.c);
 }
 
-function movePiece() {
-  // Your code here
-
+function movePiece(startStack, endStack) {
+  if (startStack === 'a' && endStack === 'b') {
+    let mover = stacks.a.pop();
+    stacks.b.push(mover);
+  } else if (startStack === 'a' && endStack === 'c') {
+    let mover = stacks.a.pop();
+    stacks.c.push(mover);
+  } else if (startStack === 'b' && endStack === 'a') {
+    let mover = stacks.b.pop();
+    stacks.a.push(mover);
+  } else if (startStack === 'b' && endStack === 'c') {
+    let mover = stacks.b.pop();
+    stacks.c.push(mover);
+  } else if (startStack === 'c' && endStack === 'a') {
+    let mover = stacks.c.pop();
+    stacks.a.push(mover);
+  } else {
+    let mover = stacks.c.pop();
+    stacks.b.push(mover);
+  }
 }
 
-function isLegal() {
-  // Your code here
-
+function isLegal(start, end) {
+  const startStack = stacks[start];
+  const endStack = stacks[end];
+  if (startStack.length === 0) {
+    return false;
+  }
+  if (endStack.length === 0) {
+    return true;
+  } else if (startStack[startStack.length - 1] > endStack[endStack.length - 1]) {
+    return false;
+  } else {
+    return true;
+  }
 }
 
 function checkForWin() {
-  // Your code here
+  if (stacks.b.length === 4 || stacks.c.length === 4) {
+    console.log('You win!')
+    return true;
+  } else {
+    return false;
+  }
+}
 
+function reset() {
+  stacks = {
+    a: [4, 3, 2, 1],
+    b: [],
+    c: []
+  };
 }
 
 function towersOfHanoi(startStack, endStack) {
-  // Your code here
-
+  movePiece(startStack, endStack);
+  isLegal(startStack, endStack);
+  if (checkForWin()) {
+    reset();
+  }
 }
 
 function getPrompt() {
@@ -69,6 +121,14 @@ if (typeof describe === 'function') {
       };
       assert.equal(isLegal('a', 'b'), false);
     });
+    it('should allow a small block on a big block', () => {
+      stacks = {
+        a: [4, 3],
+        b: [1],
+        c: [2],
+      };
+      assert.equal(isLegal('b', 'c'), true);
+    });
     it('should allow a legal move', () => {
       stacks = {
         a: [4, 3, 2, 1],
@@ -77,6 +137,14 @@ if (typeof describe === 'function') {
       };
       assert.equal(isLegal('a', 'c'), true);
     });
+    it('should only move if startStack is not empty', () => {
+      stacks = {
+        a: [4, 3, 2, 1],
+        b: [],
+        c: []
+      };
+      assert.equal(isLegal('b', 'c'), false);
+    });
   });
   describe('#checkForWin()', () => {
     it('should detect a win', () => {