#75 Update node branch split check in smt-s

Author: martti007

src/main/java/org/unicitylabs/sdk/smt/radix/SparseMerkleTree.java

@@ -105,7 +105,7 @@ private static Branch buildTree(Branch branch, BigInteger keyPath, byte[] key, b
     NodeBranch nodeBranch = (NodeBranch) branch;
 
     // if node branch is split in the middle
-    if (commonPath.getPath().compareTo(branch.getPath()) < 0) {
+    if (!commonPath.getPath().equals(branch.getPath())) {
       LeafBranch newBranch = new PendingLeafBranch(keyPath, key, value);
       return new PendingNodeBranch(commonPath.getPath(), commonPath.getLength(),
               isRight ? branch : newBranch, isRight ? newBranch : branch);

src/main/java/org/unicitylabs/sdk/smt/radixsum/SparseMerkleSumTree.java

@@ -114,7 +114,7 @@ private static Branch buildTree(Branch branch, BigInteger keyPath, byte[] key, b
     NodeBranch nodeBranch = (NodeBranch) branch;
 
     // if node branch is split in the middle
-    if (commonPath.getPath().compareTo(branch.getPath()) < 0) {
+    if (!commonPath.getPath().equals(branch.getPath())) {
       LeafBranch newBranch = new PendingLeafBranch(keyPath, key, data, value);
       return new PendingNodeBranch(commonPath.getPath(), commonPath.getLength(),
               isRight ? branch : newBranch, isRight ? newBranch : branch);