diff --git a/native/Android.mk b/native/Android.mk
index d2537f0..5dcc1e5 100644
--- a/native/Android.mk
+++ b/native/Android.mk
@@ -46,15 +46,19 @@
 
 LOCAL_MODULE_TAGS := user
 
+# For STL
+LOCAL_C_INCLUDES += external/stlport/stlport bionic
+LOCAL_SHARED_LIBRARIES += libstlport
+
 ifeq ($(FLAG_DO_PROFILE), true)
     $(warning Making profiling version of native library)
     LOCAL_CFLAGS += -DFLAG_DO_PROFILE
-    LOCAL_SHARED_LIBRARIES := libcutils libutils
+    LOCAL_SHARED_LIBRARIES += libcutils libutils
 else # FLAG_DO_PROFILE
 ifeq ($(FLAG_DBG), true)
     $(warning Making debug version of native library)
     LOCAL_CFLAGS += -DFLAG_DBG
-    LOCAL_SHARED_LIBRARIES := libcutils libutils
+    LOCAL_SHARED_LIBRARIES += libcutils libutils
 endif # FLAG_DBG
 endif # FLAG_DO_PROFILE
 
diff --git a/native/src/defines.h b/native/src/defines.h
index ef1beb9..b59f623 100644
--- a/native/src/defines.h
+++ b/native/src/defines.h
@@ -101,6 +101,7 @@
 #define DEBUG_PROXIMITY_INFO true
 #define DEBUG_CORRECTION false
 #define DEBUG_CORRECTION_FREQ true
+#define DEBUG_WORDS_PRIORITY_QUEUE true
 
 #define DUMP_WORD(word, length) do { dumpWord(word, length); } while(0)
 
@@ -125,6 +126,7 @@
 #define DEBUG_PROXIMITY_INFO false
 #define DEBUG_CORRECTION false
 #define DEBUG_CORRECTION_FREQ false
+#define DEBUG_WORDS_PRIORITY_QUEUE false
 
 #define DUMP_WORD(word, length)
 
diff --git a/native/src/unigram_dictionary.cpp b/native/src/unigram_dictionary.cpp
index 647bfde..e17e7d0 100644
--- a/native/src/unigram_dictionary.cpp
+++ b/native/src/unigram_dictionary.cpp
@@ -49,10 +49,12 @@
         LOGI("UnigramDictionary - constructor");
     }
     mCorrection = new Correction(typedLetterMultiplier, fullWordMultiplier);
+    mWordsPriorityQueue = new WordsPriorityQueue(maxWords, maxWordLength);
 }
 
 UnigramDictionary::~UnigramDictionary() {
     delete mCorrection;
+    delete mWordsPriorityQueue;
 }
 
 static inline unsigned int getCodesBufferSize(const int* codes, const int codesSize,
@@ -88,7 +90,7 @@
 void UnigramDictionary::getWordWithDigraphSuggestionsRec(ProximityInfo *proximityInfo,
         const int *xcoordinates, const int* ycoordinates, const int *codesBuffer,
         const int codesBufferSize, const int flags, const int* codesSrc, const int codesRemain,
-        const int currentDepth, int* codesDest, unsigned short* outWords, int* frequencies) {
+        const int currentDepth, int* codesDest) {
 
     if (currentDepth < MAX_UMLAUT_SEARCH_DEPTH) {
         for (int i = 0; i < codesRemain; ++i) {
@@ -105,8 +107,7 @@
                 getWordWithDigraphSuggestionsRec(proximityInfo, xcoordinates, ycoordinates,
                         codesBuffer, codesBufferSize, flags,
                         codesSrc + (i + 1) * MAX_PROXIMITY_CHARS, codesRemain - i - 1,
-                        currentDepth + 1, codesDest + i * MAX_PROXIMITY_CHARS, outWords,
-                        frequencies);
+                        currentDepth + 1, codesDest + i * MAX_PROXIMITY_CHARS);
 
                 // Copy the second char of the digraph in place, then continue processing on
                 // the remaining part of the word.
@@ -115,8 +116,7 @@
                         BYTES_IN_ONE_CHAR);
                 getWordWithDigraphSuggestionsRec(proximityInfo, xcoordinates, ycoordinates,
                         codesBuffer, codesBufferSize, flags, codesSrc + i * MAX_PROXIMITY_CHARS,
-                        codesRemain - i, currentDepth + 1, codesDest + i * MAX_PROXIMITY_CHARS,
-                        outWords, frequencies);
+                        codesRemain - i, currentDepth + 1, codesDest + i * MAX_PROXIMITY_CHARS);
                 return;
             }
         }
@@ -132,8 +132,7 @@
         memcpy(codesDest, codesSrc, remainingBytes);
 
     getWordSuggestions(proximityInfo, xcoordinates, ycoordinates, codesBuffer,
-            (codesDest - codesBuffer) / MAX_PROXIMITY_CHARS + codesRemain, outWords, frequencies,
-            flags);
+            (codesDest - codesBuffer) / MAX_PROXIMITY_CHARS + codesRemain, flags);
 }
 
 int UnigramDictionary::getSuggestions(ProximityInfo *proximityInfo, const int *xcoordinates,
@@ -144,28 +143,24 @@
     { // Incrementally tune the word and try all possibilities
         int codesBuffer[getCodesBufferSize(codes, codesSize, MAX_PROXIMITY_CHARS)];
         getWordWithDigraphSuggestionsRec(proximityInfo, xcoordinates, ycoordinates, codesBuffer,
-                codesSize, flags, codes, codesSize, 0, codesBuffer, outWords, frequencies);
+                codesSize, flags, codes, codesSize, 0, codesBuffer);
     } else { // Normal processing
-        getWordSuggestions(proximityInfo, xcoordinates, ycoordinates, codes, codesSize,
-                outWords, frequencies, flags);
+        getWordSuggestions(proximityInfo, xcoordinates, ycoordinates, codes, codesSize, flags);
     }
 
     PROF_START(20);
-    // Get the word count
-    int suggestedWordsCount = 0;
-    while (suggestedWordsCount < MAX_WORDS && mFrequencies[suggestedWordsCount] > 0) {
-        suggestedWordsCount++;
-    }
+    const int suggestedWordsCount =
+            mWordsPriorityQueue->outputSuggestions(frequencies, outWords);
 
     if (DEBUG_DICT) {
         LOGI("Returning %d words", suggestedWordsCount);
         /// Print the returned words
         for (int j = 0; j < suggestedWordsCount; ++j) {
 #ifdef FLAG_DBG
-            short unsigned int* w = mOutputChars + j * MAX_WORD_LENGTH;
+            short unsigned int* w = outWords + j * MAX_WORD_LENGTH;
             char s[MAX_WORD_LENGTH];
             for (int i = 0; i <= MAX_WORD_LENGTH; i++) s[i] = w[i];
-            LOGI("%s %i", s, mFrequencies[j]);
+            LOGI("%s %i", s, frequencies[j]);
 #endif
         }
     }
@@ -176,12 +171,12 @@
 
 void UnigramDictionary::getWordSuggestions(ProximityInfo *proximityInfo,
         const int *xcoordinates, const int *ycoordinates, const int *codes, const int codesSize,
-        unsigned short *outWords, int *frequencies, const int flags) {
+        const int flags) {
 
     PROF_OPEN;
     PROF_START(0);
     initSuggestions(
-            proximityInfo, xcoordinates, ycoordinates, codes, codesSize, outWords, frequencies);
+            proximityInfo, xcoordinates, ycoordinates, codes, codesSize);
     if (DEBUG_DICT) assert(codesSize == mInputLength);
 
     const int maxDepth = min(mInputLength * MAX_DEPTH_MULTIPLIER, MAX_WORD_LENGTH);
@@ -241,71 +236,19 @@
 }
 
 void UnigramDictionary::initSuggestions(ProximityInfo *proximityInfo, const int *xCoordinates,
-        const int *yCoordinates, const int *codes, const int codesSize,
-        unsigned short *outWords, int *frequencies) {
+        const int *yCoordinates, const int *codes, const int codesSize) {
     if (DEBUG_DICT) {
         LOGI("initSuggest");
     }
-    mFrequencies = frequencies;
-    mOutputChars = outWords;
     mInputLength = codesSize;
     proximityInfo->setInputParams(codes, codesSize, xCoordinates, yCoordinates);
     mProximityInfo = proximityInfo;
+    mWordsPriorityQueue->clear();
 }
 
-// TODO: We need to optimize addWord by using STL or something
 // TODO: This needs to take an const unsigned short* and not tinker with its contents
-bool UnigramDictionary::addWord(unsigned short *word, int length, int frequency) {
-    word[length] = 0;
-    if (DEBUG_DICT && DEBUG_SHOW_FOUND_WORD) {
-#ifdef FLAG_DBG
-        char s[length + 1];
-        for (int i = 0; i <= length; i++) s[i] = word[i];
-        LOGI("Found word = %s, freq = %d", s, frequency);
-#endif
-    }
-    if (length > MAX_WORD_LENGTH) {
-        if (DEBUG_DICT) {
-            LOGI("Exceeded max word length.");
-        }
-        return false;
-    }
-
-    // Find the right insertion point
-    int insertAt = 0;
-    while (insertAt < MAX_WORDS) {
-        // TODO: How should we sort words with the same frequency?
-        if (frequency > mFrequencies[insertAt]) {
-            break;
-        }
-        insertAt++;
-    }
-    if (insertAt < MAX_WORDS) {
-        if (DEBUG_DICT) {
-#ifdef FLAG_DBG
-            char s[length + 1];
-            for (int i = 0; i <= length; i++) s[i] = word[i];
-            LOGI("Added word = %s, freq = %d, %d", s, frequency, S_INT_MAX);
-#endif
-        }
-        memmove((char*) mFrequencies + (insertAt + 1) * sizeof(mFrequencies[0]),
-               (char*) mFrequencies + insertAt * sizeof(mFrequencies[0]),
-               (MAX_WORDS - insertAt - 1) * sizeof(mFrequencies[0]));
-        mFrequencies[insertAt] = frequency;
-        memmove((char*) mOutputChars + (insertAt + 1) * MAX_WORD_LENGTH * sizeof(short),
-               (char*) mOutputChars + insertAt * MAX_WORD_LENGTH * sizeof(short),
-               (MAX_WORDS - insertAt - 1) * sizeof(short) * MAX_WORD_LENGTH);
-        unsigned short *dest = mOutputChars + insertAt * MAX_WORD_LENGTH;
-        while (length--) {
-            *dest++ = *word++;
-        }
-        *dest = 0; // NULL terminate
-        if (DEBUG_DICT) {
-            LOGI("Added word at %d", insertAt);
-        }
-        return true;
-    }
-    return false;
+void UnigramDictionary::addWord(unsigned short *word, int length, int frequency) {
+    mWordsPriorityQueue->push(frequency, word, length);
 }
 
 static const char QUOTE = '\'';
diff --git a/native/src/unigram_dictionary.h b/native/src/unigram_dictionary.h
index 4f4fef2..506ed62 100644
--- a/native/src/unigram_dictionary.h
+++ b/native/src/unigram_dictionary.h
@@ -22,6 +22,7 @@
 #include "correction_state.h"
 #include "defines.h"
 #include "proximity_info.h"
+#include "words_priority_queue.h"
 
 namespace latinime {
 
@@ -73,18 +74,16 @@
 private:
 
     void getWordSuggestions(ProximityInfo *proximityInfo, const int *xcoordinates,
-            const int *ycoordinates, const int *codes, const int codesSize,
-            unsigned short *outWords, int *frequencies, const int flags);
+            const int *ycoordinates, const int *codes, const int codesSize, const int flags);
     bool isDigraph(const int* codes, const int i, const int codesSize) const;
     void getWordWithDigraphSuggestionsRec(ProximityInfo *proximityInfo,
         const int *xcoordinates, const int* ycoordinates, const int *codesBuffer,
         const int codesBufferSize, const int flags, const int* codesSrc, const int codesRemain,
-        const int currentDepth, int* codesDest, unsigned short* outWords, int* frequencies);
+        const int currentDepth, int* codesDest);
     void initSuggestions(ProximityInfo *proximityInfo, const int *xcoordinates,
-            const int *ycoordinates, const int *codes, const int codesSize,
-            unsigned short *outWords, int *frequencies);
+            const int *ycoordinates, const int *codes, const int codesSize);
     void getSuggestionCandidates(const bool useFullEditDistance);
-    bool addWord(unsigned short *word, int length, int frequency);
+    void addWord(unsigned short *word, int length, int frequency);
     void getSplitTwoWordsSuggestion(const int inputLength, Correction *correction);
     void getMissingSpaceWords(const int inputLength, const int missingSpacePos,
             Correction *correction, const bool useFullEditDistance);
@@ -123,8 +122,7 @@
     };
     static const struct digraph_t { int first; int second; } GERMAN_UMLAUT_DIGRAPHS[];
 
-    int *mFrequencies;
-    unsigned short *mOutputChars;
+    WordsPriorityQueue *mWordsPriorityQueue;
     ProximityInfo *mProximityInfo;
     Correction *mCorrection;
     int mInputLength;
diff --git a/native/src/words_priority_queue.h b/native/src/words_priority_queue.h
new file mode 100644
index 0000000..366b1b6
--- /dev/null
+++ b/native/src/words_priority_queue.h
@@ -0,0 +1,146 @@
+/*
+ * 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_WORDS_PRIORITY_QUEUE_H
+#define LATINIME_WORDS_PRIORITY_QUEUE_H
+
+#include <iostream>
+#include <queue>
+#include "defines.h"
+
+namespace latinime {
+
+class WordsPriorityQueue {
+private:
+    class SuggestedWord {
+    public:
+        int mScore;
+        unsigned short mWord[MAX_WORD_LENGTH_INTERNAL];
+        int mWordLength;
+        bool mUsed;
+
+        void setParams(int score, unsigned short* word, int wordLength) {
+            mScore = score;
+            mWordLength = wordLength;
+            memcpy(mWord, word, sizeof(unsigned short) * wordLength);
+            mUsed = true;
+        }
+    };
+
+    struct wordComparator {
+        bool operator ()(SuggestedWord * left, SuggestedWord * right) {
+            return left->mScore > right->mScore;
+        }
+    };
+
+    SuggestedWord* getFreeSuggestedWord(int score, unsigned short* word,
+            int wordLength) {
+        for (unsigned int i = 0; i < MAX_WORD_LENGTH; ++i) {
+            if (!mSuggestedWords[i].mUsed) {
+                mSuggestedWords[i].setParams(score, word, wordLength);
+                return &mSuggestedWords[i];
+            }
+        }
+        return 0;
+    }
+
+    typedef std::priority_queue<SuggestedWord*, std::vector<SuggestedWord*>,
+            wordComparator> Suggestions;
+    Suggestions mSuggestions;
+    const unsigned int MAX_WORDS;
+    const unsigned int MAX_WORD_LENGTH;
+    SuggestedWord* mSuggestedWords;
+
+public:
+    WordsPriorityQueue(int maxWords, int maxWordLength) :
+            MAX_WORDS((unsigned int) maxWords), MAX_WORD_LENGTH(
+                    (unsigned int) maxWordLength) {
+        mSuggestedWords = new SuggestedWord[maxWordLength];
+        for (int i = 0; i < maxWordLength; ++i) {
+            mSuggestedWords[i].mUsed = false;
+        }
+    }
+    ~WordsPriorityQueue() {
+        delete[] mSuggestedWords;
+    }
+
+    void push(int score, unsigned short* word, int wordLength) {
+        SuggestedWord* sw = 0;
+        if (mSuggestions.size() >= MAX_WORDS) {
+            sw = mSuggestions.top();
+            const int minScore = sw->mScore;
+            if (minScore >= score) {
+                return;
+            } else {
+                sw->mUsed = false;
+                mSuggestions.pop();
+            }
+        }
+        if (sw == 0) {
+            sw = getFreeSuggestedWord(score, word, wordLength);
+        } else {
+            sw->setParams(score, word, wordLength);
+        }
+        if (sw == 0) {
+            LOGE("SuggestedWord is accidentally null.");
+            return;
+        }
+        if (DEBUG_WORDS_PRIORITY_QUEUE) {
+            LOGI("Push word. %d, %d", score, wordLength);
+            DUMP_WORD(word, wordLength);
+        }
+        mSuggestions.push(sw);
+    }
+
+    int outputSuggestions(int *frequencies, unsigned short *outputChars) {
+        const unsigned int size = min(MAX_WORDS, mSuggestions.size());
+        int index = size - 1;
+        while (!mSuggestions.empty() && index >= 0) {
+            SuggestedWord* sw = mSuggestions.top();
+            if (DEBUG_WORDS_PRIORITY_QUEUE) {
+                LOGI("dump word. %d", sw->mScore);
+                DUMP_WORD(sw->mWord, sw->mWordLength);
+            }
+            const unsigned int wordLength = sw->mWordLength;
+            char* targetAdr = (char*) outputChars
+                    + (index) * MAX_WORD_LENGTH * sizeof(short);
+            frequencies[index] = sw->mScore;
+            memcpy(targetAdr, sw->mWord, (wordLength) * sizeof(short));
+            if (wordLength < MAX_WORD_LENGTH) {
+                ((unsigned short*) targetAdr)[wordLength] = 0;
+            }
+            sw->mUsed = false;
+            mSuggestions.pop();
+            --index;
+        }
+        return size;
+    }
+
+    void clear() {
+        while (!mSuggestions.empty()) {
+            SuggestedWord* sw = mSuggestions.top();
+            if (DEBUG_WORDS_PRIORITY_QUEUE) {
+                LOGI("Clear word. %d", sw->mScore);
+                DUMP_WORD(sw->mWord, sw->mWordLength);
+            }
+            sw->mUsed = false;
+            mSuggestions.pop();
+        }
+    }
+};
+}
+
+#endif // LATINIME_WORDS_PRIORITY_QUEUE_H