diff --git a/native/src/correction.cpp b/native/src/correction.cpp
index 6d682c0..a931a61 100644
--- a/native/src/correction.cpp
+++ b/native/src/correction.cpp
@@ -52,6 +52,11 @@
     mSkippedOutputIndex = -1;
 }
 
+void Correction::initCorrectionState(
+        const int rootPos, const int childCount, const bool traverseAll) {
+    mCorrectionStates[0].init(rootPos, childCount, traverseAll);
+}
+
 void Correction::setCorrectionParams(const int skipPos, const int excessivePos,
         const int transposedPos, const int spaceProximityPos, const int missingSpacePos) {
     mSkipPos = skipPos;
@@ -90,22 +95,25 @@
             inputIndex, outputIndex, mMatchedCharCount, freq, sameLength, this);
 }
 
-void Correction::initProcessState(const int matchCount, const int inputIndex,
-        const int outputIndex, const bool traverseAllNodes, const int diffs) {
-    mMatchedCharCount = matchCount;
-    mInputIndex = inputIndex;
+bool Correction::initProcessState(const int outputIndex) {
+    if (mCorrectionStates[outputIndex].mChildCount <= 0) {
+        return false;
+    }
     mOutputIndex = outputIndex;
-    mTraverseAllNodes = traverseAllNodes;
-    mDiffs = diffs;
+    --(mCorrectionStates[outputIndex].mChildCount);
+    mMatchedCharCount = mCorrectionStates[outputIndex].mMatchedCount;
+    mInputIndex = mCorrectionStates[outputIndex].mInputIndex;
+    mTraverseAllNodes = mCorrectionStates[outputIndex].mTraverseAll;
+    mDiffs = mCorrectionStates[outputIndex].mDiffs;
+    return true;
 }
 
-void Correction::getProcessState(int *matchedCount, int *inputIndex, int *outputIndex,
-        bool *traverseAllNodes, int *diffs) {
-    *matchedCount = mMatchedCharCount;
-    *inputIndex = mInputIndex;
-    *outputIndex = mOutputIndex;
-    *traverseAllNodes = mTraverseAllNodes;
-    *diffs = mDiffs;
+int Correction::goDownTree(
+        const int parentIndex, const int childCount, const int firstChildPos) {
+    mCorrectionStates[mOutputIndex].mParentIndex = parentIndex;
+    mCorrectionStates[mOutputIndex].mChildCount = childCount;
+    mCorrectionStates[mOutputIndex].mSiblingPos = firstChildPos;
+    return mOutputIndex;
 }
 
 void Correction::charMatched() {
@@ -133,6 +141,13 @@
 
 void Correction::incrementOutputIndex() {
     ++mOutputIndex;
+    mCorrectionStates[mOutputIndex].mParentIndex = mCorrectionStates[mOutputIndex - 1].mParentIndex;
+    mCorrectionStates[mOutputIndex].mChildCount = mCorrectionStates[mOutputIndex - 1].mChildCount;
+    mCorrectionStates[mOutputIndex].mSiblingPos = mCorrectionStates[mOutputIndex - 1].mSiblingPos;
+    mCorrectionStates[mOutputIndex].mMatchedCount = mMatchedCharCount;
+    mCorrectionStates[mOutputIndex].mInputIndex = mInputIndex;
+    mCorrectionStates[mOutputIndex].mTraverseAll = mTraverseAllNodes;
+    mCorrectionStates[mOutputIndex].mDiffs = mDiffs;
 }
 
 void Correction::startTraverseAll() {
diff --git a/native/src/correction.h b/native/src/correction.h
index ae6c7a4..590d62f 100644
--- a/native/src/correction.h
+++ b/native/src/correction.h
@@ -18,6 +18,7 @@
 #define LATINIME_CORRECTION_H
 
 #include <stdint.h>
+#include "correction_state.h"
 
 #include "defines.h"
 
@@ -39,11 +40,14 @@
     Correction(const int typedLetterMultiplier, const int fullWordMultiplier);
     void initCorrection(
             const ProximityInfo *pi, const int inputLength, const int maxWordLength);
+    void initCorrectionState(const int rootPos, const int childCount, const bool traverseAll);
+
+    // TODO: remove
     void setCorrectionParams(const int skipPos, const int excessivePos, const int transposedPos,
             const int spaceProximityPos, const int missingSpacePos);
     void checkState();
-    void initProcessState(const int matchCount, const int inputIndex, const int outputIndex,
-            const bool traverseAllNodes, const int diffs);
+    bool initProcessState(const int index);
+
     void getProcessState(int *matchedCount, int *inputIndex, int *outputIndex,
             bool *traverseAllNodes, int *diffs);
     int getOutputIndex();
@@ -80,6 +84,22 @@
     int getDiffs() const {
         return mDiffs;
     }
+
+    /////////////////////////
+    // Tree helper methods
+    int goDownTree(const int parentIndex, const int childCount, const int firstChildPos);
+
+    inline int getTreeSiblingPos(const int index) const {
+        return mCorrectionStates[index].mSiblingPos;
+    }
+
+    inline void setTreeSiblingPos(const int index, const int pos) {
+        mCorrectionStates[index].mSiblingPos = pos;
+    }
+
+    inline int getTreeParentIndex(const int index) const {
+        return mCorrectionStates[index].mParentIndex;
+    }
 private:
     void charMatched();
     void incrementInputIndex();
@@ -116,6 +136,8 @@
     bool mTraverseAllNodes;
     unsigned short mWord[MAX_WORD_LENGTH_INTERNAL];
 
+    CorrectionState mCorrectionStates[MAX_WORD_LENGTH_INTERNAL];
+
     inline bool isQuote(const unsigned short c);
     inline CorrectionType processSkipChar(const int32_t c, const bool isTerminal);
 
diff --git a/native/src/correction_state.h b/native/src/correction_state.h
new file mode 100644
index 0000000..1fe02b8
--- /dev/null
+++ b/native/src/correction_state.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_CORRECTION_STATE_H
+#define LATINIME_CORRECTION_STATE_H
+
+#include <stdint.h>
+
+#include "defines.h"
+
+namespace latinime {
+
+class CorrectionState {
+public:
+    int mParentIndex;
+    int mMatchedCount;
+    int mChildCount;
+    int mInputIndex;
+    int mDiffs;
+    int mSiblingPos;
+    bool mTraverseAll;
+
+    inline void init(const int rootPos, const int childCount, const bool traverseAll) {
+        set(-1, 0, childCount, 0, 0, rootPos, traverseAll);
+    }
+
+private:
+    inline void set(const int parentIndex, const int matchedCount, const int childCount,
+            const int inputIndex, const int diffs, const int siblingPos,
+            const bool traverseAll) {
+        mParentIndex = parentIndex;
+        mMatchedCount = matchedCount;
+        mChildCount = childCount;
+        mInputIndex = inputIndex;
+        mDiffs = diffs;
+        mSiblingPos = siblingPos;
+        mTraverseAll = traverseAll;
+    }
+};
+} // namespace latinime
+#endif // LATINIME_CORRECTION_STATE_H
diff --git a/native/src/unigram_dictionary.cpp b/native/src/unigram_dictionary.cpp
index df1a2e2..bbfaea4 100644
--- a/native/src/unigram_dictionary.cpp
+++ b/native/src/unigram_dictionary.cpp
@@ -352,44 +352,28 @@
     int rootPosition = ROOT_POS;
     // Get the number of children of root, then increment the position
     int childCount = Dictionary::getCount(DICT_ROOT, &rootPosition);
-    int depth = 0;
+    int outputIndex = 0;
 
-    mStackChildCount[0] = childCount;
-    mStackTraverseAll[0] = (mInputLength <= 0);
-    mStackInputIndex[0] = 0;
-    mStackDiffs[0] = 0;
-    mStackSiblingPos[0] = rootPosition;
-    mStackOutputIndex[0] = 0;
-    mStackMatchedCount[0] = 0;
+    mCorrection->initCorrectionState(rootPosition, childCount, (mInputLength <= 0));
 
     // Depth first search
-    while (depth >= 0) {
-        if (mStackChildCount[depth] > 0) {
-            --mStackChildCount[depth];
-            int siblingPos = mStackSiblingPos[depth];
+    while (outputIndex >= 0) {
+        if (mCorrection->initProcessState(outputIndex)) {
+            int siblingPos = mCorrection->getTreeSiblingPos(outputIndex);
             int firstChildPos;
-            mCorrection->initProcessState(
-                    mStackMatchedCount[depth], mStackInputIndex[depth], mStackOutputIndex[depth],
-                    mStackTraverseAll[depth], mStackDiffs[depth]);
 
-            // needsToTraverseChildrenNodes should be false
             const bool needsToTraverseChildrenNodes = processCurrentNode(siblingPos,
                     mCorrection, &childCount, &firstChildPos, &siblingPos);
             // Update next sibling pos
-            mStackSiblingPos[depth] = siblingPos;
+            mCorrection->setTreeSiblingPos(outputIndex, siblingPos);
+
             if (needsToTraverseChildrenNodes) {
                 // Goes to child node
-                ++depth;
-                mStackChildCount[depth] = childCount;
-                mStackSiblingPos[depth] = firstChildPos;
-
-                mCorrection->getProcessState(&mStackMatchedCount[depth],
-                        &mStackInputIndex[depth], &mStackOutputIndex[depth],
-                        &mStackTraverseAll[depth], &mStackDiffs[depth]);
+                outputIndex = mCorrection->goDownTree(outputIndex, childCount, firstChildPos);
             }
         } else {
             // Goes to parent sibling node
-            --depth;
+            outputIndex = mCorrection->getTreeParentIndex(outputIndex);
         }
     }
 }
diff --git a/native/src/unigram_dictionary.h b/native/src/unigram_dictionary.h
index 8bcd7ce..cfe63ff 100644
--- a/native/src/unigram_dictionary.h
+++ b/native/src/unigram_dictionary.h
@@ -19,6 +19,7 @@
 
 #include <stdint.h>
 #include "correction.h"
+#include "correction_state.h"
 #include "defines.h"
 #include "proximity_info.h"
 
@@ -134,13 +135,9 @@
     // MAX_WORD_LENGTH_INTERNAL must be bigger than MAX_WORD_LENGTH
     unsigned short mWord[MAX_WORD_LENGTH_INTERNAL];
 
-    int mStackMatchedCount[MAX_WORD_LENGTH_INTERNAL];
-    int mStackChildCount[MAX_WORD_LENGTH_INTERNAL];
-    bool mStackTraverseAll[MAX_WORD_LENGTH_INTERNAL];
-    int mStackInputIndex[MAX_WORD_LENGTH_INTERNAL];
-    int mStackDiffs[MAX_WORD_LENGTH_INTERNAL];
-    int mStackSiblingPos[MAX_WORD_LENGTH_INTERNAL];
-    int mStackOutputIndex[MAX_WORD_LENGTH_INTERNAL];
+    int mStackChildCount[MAX_WORD_LENGTH_INTERNAL];// TODO: remove
+    int mStackInputIndex[MAX_WORD_LENGTH_INTERNAL];// TODO: remove
+    int mStackSiblingPos[MAX_WORD_LENGTH_INTERNAL];// TODO: remove
 };
 } // namespace latinime