Account for starting in phase 2

lib/solve.js

@@ -776,18 +776,22 @@
 
       // Initialize phase 2 coordinates
       init2(top = true) {
-        if (this.parent === null) {
+        if (this.parent === null && !top) {
           return;
         }
-        // For other states, the phase 2 state is computed based on
-        // parent's state.
+        // If parent is null then this is the initial call which must mean
+        // the cube started in phase 2 so there is no need for this
         // Already assigned for the initial state
-        this.parent.init2(false);
-        this.URFtoDLF = this.move('URFtoDLF', this.parent.URFtoDLF, this.lastMove);
-        this.FRtoBR = this.move('FRtoBR', this.parent.FRtoBR, this.lastMove);
-        this.parity = this.move('parity', this.parent.parity, this.lastMove);
-        this.URtoUL = this.move('URtoUL', this.parent.URtoUL, this.lastMove);
-        this.UBtoDF = this.move('UBtoDF', this.parent.UBtoDF, this.lastMove);
+        if (this.parent !== null) {
+          // For other states, the phase 2 state is computed based on
+          // parent's state.
+          this.parent.init2(false, false);
+          this.URFtoDLF = this.move('URFtoDLF', this.parent.URFtoDLF, this.lastMove);
+          this.FRtoBR = this.move('FRtoBR', this.parent.FRtoBR, this.lastMove);
+          this.parity = this.move('parity', this.parent.parity, this.lastMove);
+          this.URtoUL = this.move('URtoUL', this.parent.URtoUL, this.lastMove);
+          this.UBtoDF = this.move('UBtoDF', this.parent.UBtoDF, this.lastMove);
+        }
         if (top) {
           // This is the initial phase 2 state. Get the URtoDF coordinate
           // by merging URtoUL and UBtoDF
@@ -813,14 +817,14 @@
     solution = null;
     phase1search = function(state) {
       var depth, m, ref, results;
-      depth = 0;
       results = [];
-      for (depth = m = 1, ref = maxDepth; (1 <= ref ? m <= ref : m >= ref); depth = 1 <= ref ? ++m : --m) {
+      for (depth = m = 0, ref = maxDepth; (0 <= ref ? m <= ref : m >= ref); depth = 0 <= ref ? ++m : --m) {
         phase1(state, depth);
         if (solution !== null) {
           break;
+        } else {
+          results.push(void 0);
         }
-        results.push(depth++);
       }
       return results;
     };
@@ -859,12 +863,13 @@
       // Initialize phase 2 coordinates
       state.init2();
       results = [];
-      for (depth = m = 1, ref = maxDepth - state.depth; (1 <= ref ? m <= ref : m >= ref); depth = 1 <= ref ? ++m : --m) {
+      for (depth = m = 0, ref = maxDepth - state.depth; (0 <= ref ? m <= ref : m >= ref); depth = 0 <= ref ? ++m : --m) {
         phase2(state, depth);
         if (solution !== null) {
           break;
+        } else {
+          results.push(void 0);
         }
-        results.push(depth++);
       }
       return results;
     };
@@ -904,11 +909,8 @@
     state = freeStates.pop().init(this);
     phase1search(state);
     freeStates.push(state);
-    // Trim the trailing space
-    if (solution.length > 0) {
-      solution = solution.substring(0, solution.length - 1);
-    }
-    return solution;
+    // Trim the trailing space and return
+    return solution.trim();
   };
 
   faceNums = {

spec/cube.spec.coffee

@@ -53,8 +53,24 @@ describe 'Cube', ->
     moves = Cube.inverse "F B' R"
     expect(moves).toBe "R' B F'"
 
-  # ignore because Travis is slow
-  xit 'should solve a solved cube :) ', ->
+  # It seems Cube init state is reset between tests so we keep it all in one
+  # Due to Travis being slow we skip this but if you change algorithm you should
+  # run it locally
+  xit 'should solve cubes', ->
     Cube.initSolver()
+    # Should solve empty cube
     cube = new Cube
-    expect(cube.solve()).toBe "R L U2 R L F2 R2 U2 R2 F2 R2 U2 F2 L2"
+    expect(cube.solve()).toBe ""
+
+    # Should solve trivial cube efficiently
+    cube.move("U'")
+    expect(cube.solve()).toBe "U"
+
+    # Should solve random cube
+    cube = Cube.random()
+    # Should not be solved initially
+    expect(cube.isSolved()).toBeFalse
+    solution = cube.solve()
+    cube.move(solution)
+    # Solution should have solved the cube
+    expect(cube.isSolved()).toBeTrue

src/solve.coffee

@@ -579,19 +579,22 @@ Cube::solveUpright = (maxDepth=22) ->
 
     # Initialize phase 2 coordinates
     init2: (top=true) ->
-      if @parent is null
+      if @parent is null and not top
         # Already assigned for the initial state
         return
 
-      # For other states, the phase 2 state is computed based on
-      # parent's state.
-      @parent.init2(false)
+      # If parent is null then this is the initial call which must mean
+      # the cube started in phase 2 so there is no need for this
+      if @parent isnt null
+        # For other states, the phase 2 state is computed based on
+        # parent's state.
+        @parent.init2(false, false)
 
-      @URFtoDLF = @move('URFtoDLF', @parent.URFtoDLF, @lastMove)
-      @FRtoBR = @move('FRtoBR', @parent.FRtoBR, @lastMove)
-      @parity = @move('parity', @parent.parity, @lastMove)
-      @URtoUL = @move('URtoUL', @parent.URtoUL, @lastMove)
-      @UBtoDF = @move('UBtoDF', @parent.UBtoDF, @lastMove)
+        @URFtoDLF = @move('URFtoDLF', @parent.URFtoDLF, @lastMove)
+        @FRtoBR = @move('FRtoBR', @parent.FRtoBR, @lastMove)
+        @parity = @move('parity', @parent.parity, @lastMove)
+        @URtoUL = @move('URtoUL', @parent.URtoUL, @lastMove)
+        @UBtoDF = @move('UBtoDF', @parent.UBtoDF, @lastMove)
 
       if top
         # This is the initial phase 2 state. Get the URtoDF coordinate
@@ -616,7 +619,8 @@ Cube::solveUpright = (maxDepth=22) ->
   solution = null
 
   phase1search = (state) ->
-    for depth in [1..maxDepth]
+
+    for depth in [0..maxDepth]
       phase1(state, depth)
       break if solution isnt null
 
@@ -641,7 +645,7 @@ Cube::solveUpright = (maxDepth=22) ->
     # Initialize phase 2 coordinates
     state.init2()
 
-    for depth in [1..maxDepth - state.depth]
+    for depth in [0..maxDepth - state.depth]
       phase2(state, depth)
       break if solution isnt null