4 files changed, 17 insertions, 10 deletions
diff --git a/src/board.hpp b/src/board.hpp
index 687510e..4f04783 100644
--- a/src/board.hpp
+++ b/src/board.hpp
@@ -35,7 +35,10 @@ struct Position {
 
   bool operator==(const Position &) const = default;
 };
-
+struct TranspositionsEntry {
+  int depth;
+  float Eval;
+};
 struct Game {
   Piece pieces[64];
   bool turn = 1; // 1 white; 0 black
@@ -46,7 +49,7 @@ struct Game {
   bool canEnpassant = 0;
   GameState state = TURN;
   std::unordered_map<uint64_t, int> ThreeFoldMap;
-  std::unordered_map<uint64_t, float> *Transpositions = nullptr;
+  std::unordered_map<uint64_t, TranspositionsEntry> *Transpositions = nullptr;
 };
 
 struct Move {
diff --git a/src/bot.cpp b/src/bot.cpp
index 8a570e4..3394ae2 100644
--- a/src/bot.cpp
+++ b/src/bot.cpp
@@ -137,8 +137,10 @@ float minimax(int depth, Game *b, float alpha, float beta) {
   uint64_t gameHash = GenerateZobristKey(b);
 
   if (b->Transpositions->contains(gameHash)) {
-    float value = b->Transpositions->at(gameHash);
-    return value;
+    TranspositionsEntry data = b->Transpositions->at(gameHash);
+    if (data.depth >= depth) {
+      return data.Eval;
+    }
   }
   auto moves = GetLegalMoves(b);
   if (moves.size() == 0) {
@@ -181,7 +183,7 @@ float minimax(int depth, Game *b, float alpha, float beta) {
     }
   }
 
-  b->Transpositions->operator[](gameHash) = bestEval;
+  b->Transpositions->operator[](gameHash) = {depth, bestEval};
   return bestEval;
 }
 int PSTIndex(int square, bool white) { return white ? square : (56 ^ square); }
diff --git a/src/uci.cpp b/src/uci.cpp
index b4e384a..b45df57 100644
--- a/src/uci.cpp
+++ b/src/uci.cpp
@@ -45,8 +45,9 @@ Move UciToMove(string uci) {
 
   return {from, to};
 }
-Game initBoard(string startingFEN,
-               std::unordered_map<uint64_t, float> *transPositions) {
+Game initBoard(
+    string startingFEN,
+    std::unordered_map<uint64_t, TranspositionsEntry> *transPositions) {
   Game b{};
   b.enPassant = IndexToPosition(0); // default value
   b.canEnpassant = false;
@@ -71,7 +72,7 @@ Game initBoard(string startingFEN,
   return b;
 };
 void Uci() {
-  unordered_map<uint64_t, float> transpositions = {};
+  unordered_map<uint64_t, TranspositionsEntry> transpositions = {};
   Game game =
       initBoard("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
                 &transpositions);
diff --git a/src/uci.hpp b/src/uci.hpp
index 4d84215..9352c48 100644
--- a/src/uci.hpp
+++ b/src/uci.hpp
@@ -7,6 +7,7 @@
 Move UciToMove(std::string uci);
 void LogUci(const std::string &message);
 void Uci();
-Game initBoard(std::string startingFEN,
-               std::unordered_map<uint64_t, float> *transPositions);
+Game initBoard(
+    std::string startingFEN,
+    std::unordered_map<uint64_t, TranspositionsEntry> *transPositions);
 #endif /* SRC_UCI_H_ */