Quit ignoring language cost of exact matches.

Handle exact matches in DicNode::compare() and calculateFinalScore().

Bug: 8844931
Change-Id: I17c78d4e352b0a4308727229b02a8004b38468bf

native/jni/src/suggest/core/dicnode/dic_node.h

@@ -504,6 +504,12 @@ class DicNode {
         if (!right->isUsed()) {
             return false;
         }
+        // Promote exact matches to prevent them from being pruned.
+        const bool leftExactMatch = isExactMatch();
+        const bool rightExactMatch = right->isExactMatch();
+        if (leftExactMatch != rightExactMatch) {
+            return leftExactMatch;
+        }
         const float diff =
                 right->getNormalizedCompoundDistance() - getNormalizedCompoundDistance();
         static const float MIN_DIFF = 0.000001f;

native/jni/src/suggest/core/suggest.cpp

@@ -36,7 +36,6 @@ namespace latinime {
 const int Suggest::MIN_LEN_FOR_MULTI_WORD_AUTOCORRECT = 16;
 const int Suggest::MIN_CONTINUOUS_SUGGESTION_INPUT_SIZE = 2;
 const float Suggest::AUTOCORRECT_CLASSIFICATION_THRESHOLD = 0.33f;
-const int Suggest::FINAL_SCORE_PENALTY_FOR_NOT_BEST_EXACT_MATCHED_WORD = 1;
 
 /**
  * Returns a set of suggestions for the given input touch points. The commitPoint argument indicates
@@ -149,8 +148,6 @@ int Suggest::outputSuggestions(DicTraverseSession *traverseSession, int *frequen
             &doubleLetterTerminalIndex, &doubleLetterLevel);
 
     int maxScore = S_INT_MIN;
-    int bestExactMatchedNodeTerminalIndex = -1;
-    int bestExactMatchedNodeOutputWordIndex = -1;
     // Force autocorrection for obvious long multi-word suggestions when the top suggestion is
     // a long multiple words suggestion.
     // TODO: Implement a smarter auto-commit method for handling multi-word suggestions.
@@ -191,7 +188,8 @@ int Suggest::outputSuggestions(DicTraverseSession *traverseSession, int *frequen
         // TODO: Better integration with java side autocorrection logic.
         const int finalScore = SCORING->calculateFinalScore(
                 compoundDistance, traverseSession->getInputSize(),
-                (forceCommitMultiWords && terminalDicNode->hasMultipleWords())
+                terminalDicNode->isExactMatch()
+                        || (forceCommitMultiWords && terminalDicNode->hasMultipleWords())
                                 || (isValidWord && SCORING->doesAutoCorrectValidWord()));
         maxScore = max(maxScore, finalScore);
 
@@ -205,25 +203,6 @@ int Suggest::outputSuggestions(DicTraverseSession *traverseSession, int *frequen
         if (isValidWord) {
             outputTypes[outputWordIndex] = Dictionary::KIND_CORRECTION | outputTypeFlags;
             frequencies[outputWordIndex] = finalScore;
-            if (isSafeExactMatch) {
-                // Demote exact matches that are not the highest probable node among all exact
-                // matches.
-                const bool isBestTerminal = bestExactMatchedNodeTerminalIndex < 0
-                        || terminals[bestExactMatchedNodeTerminalIndex].getProbability()
-                                < terminalDicNode->getProbability();
-                const int outputWordIndexToBeDemoted = isBestTerminal ?
-                        bestExactMatchedNodeOutputWordIndex : outputWordIndex;
-                if (outputWordIndexToBeDemoted >= 0) {
-                    frequencies[outputWordIndexToBeDemoted] -=
-                            FINAL_SCORE_PENALTY_FOR_NOT_BEST_EXACT_MATCHED_WORD;
-                }
-                if (isBestTerminal) {
-                    // Updates the best exact matched node index.
-                    bestExactMatchedNodeTerminalIndex = terminalIndex;
-                    // Updates the best exact matched output word index.
-                    bestExactMatchedNodeOutputWordIndex = outputWordIndex;
-                }
-            }
             // Populate the outputChars array with the suggested word.
             const int startIndex = outputWordIndex * MAX_WORD_LENGTH;
             terminalDicNode->outputResult(&outputCodePoints[startIndex]);

native/jni/src/suggest/core/suggest.h

@@ -82,8 +82,6 @@ class Suggest : public SuggestInterface {
 
     // Threshold for autocorrection classifier
     static const float AUTOCORRECT_CLASSIFICATION_THRESHOLD;
-    // Final score penalty to exact match words that are not the most probable exact match.
-    static const int FINAL_SCORE_PENALTY_FOR_NOT_BEST_EXACT_MATCHED_WORD;
 
     const Traversal *const TRAVERSAL;
     const Scoring *const SCORING;

native/jni/src/suggest/policyimpl/typing/typing_weighting.h

@@ -169,12 +169,7 @@ class TypingWeighting : public Weighting {
 
     float getTerminalLanguageCost(const DicTraverseSession *const traverseSession,
             const DicNode *const dicNode, const float dicNodeLanguageImprobability) const {
-        // We promote exact matches here to prevent them from being pruned. The final score of
+        return dicNodeLanguageImprobability * ScoringParams::DISTANCE_WEIGHT_LANGUAGE;
-        // exact match nodes might be demoted later in Suggest::outputSuggestions if there are
-        // multiple exact matches.
-        const float languageImprobability = (dicNode->isExactMatch()) ?
-                0.0f : dicNodeLanguageImprobability;
-        return languageImprobability * ScoringParams::DISTANCE_WEIGHT_LANGUAGE;
     }
 
     AK_FORCE_INLINE bool needsToNormalizeCompoundDistance() const {