Algebraic data types: Difference between revisions

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@@ Line 712: / Line 712: @@
                  | black(ColoredTree left, ColoredTree right);
-// Count the number of red nodes
+// Count the number of black nodes
-public int cntRed(ColoredTree t){
+public int cntBlack(ColoredTree t){
    int c = 0;
    visit(t) {
-     case red(_,_): c = c + 1;
+     case black(_,_): c += 1;
    };
    return c;
 }
+// Returns if a tree is balanced
+public bool balance(ColoredTree t){
+   visit(t){
+     case black(a,b): if (cntBlack(a) == cntBlack(b)) true; else return false;
+     case red(a,b): if (cntBlack(a) == cntBlack(b)) true; else return false;
+     }
+   return true;
+}
 // Compute the sum of all integer leaves
 public int addLeaves(ColoredTree t){
    int c = 0;
    visit(t) {
-     case leaf(int N): c = c + N;
+     case leaf(int N): c += N;
    };
    return c;