tuneup sampling in C++(with classic functions) #59

*tuneup sampling in C++ *revert *replace for loop with iota
HenryRLee · Oct 21, 2021 · 18e5bf9 · 18e5bf9
1 parent 461cd14
commit 18e5bf9
Showing 1 changed file with 46 additions and 37 deletions.
diff --git a/cpp/benchmark/benchmark.cc b/cpp/benchmark/benchmark.cc
@@ -1,5 +1,6 @@
 #include <algorithm>
 #include <vector>
+#include <array>
 #include <set>
 #include <chrono>
 #include <random>
@@ -10,11 +11,11 @@ using namespace phevaluator;
 
 static void EvaluateAllFiveCards(benchmark::State& state) {
   for (auto _ : state) {
-    for(int a = 0; a < 48; a++) {
-      for(int b = a + 1; b < 49; b++) {
-        for(int c = b + 1; c < 50; c++) {
-          for(int d = c + 1; d < 51; d++) {
-            for(int e = d + 1; e < 52; e++) {
+    for (int a = 0; a < 48; a++) {
+      for (int b = a + 1; b < 49; b++) {
+        for (int c = b + 1; c < 50; c++) {
+          for (int d = c + 1; d < 51; d++) {
+            for (int e = d + 1; e < 52; e++) {
               EvaluateCards(a, b, c, d, e);
             }
           }
@@ -27,12 +28,12 @@ BENCHMARK(EvaluateAllFiveCards);
 
 static void EvaluateAllSixCards(benchmark::State& state) {
   for (auto _ : state) {
-    for(int a = 0; a < 47; a++) {
-      for(int b = a + 1; b < 48; b++) {
-        for(int c = b + 1; c < 49; c++) {
-          for(int d = c + 1; d < 50; d++) {
-            for(int e = d + 1; e < 51; e++) {
-              for(int f = e + 1; f < 52; f++) {
+    for (int a = 0; a < 47; a++) {
+      for (int b = a + 1; b < 48; b++) {
+        for (int c = b + 1; c < 49; c++) {
+          for (int d = c + 1; d < 50; d++) {
+            for (int e = d + 1; e < 51; e++) {
+              for (int f = e + 1; f < 52; f++) {
                 EvaluateCards(a, b, c, d, e, f);
               }
             }
@@ -46,13 +47,13 @@ BENCHMARK(EvaluateAllSixCards);
 
 static void EvaluateAllSevenCards(benchmark::State& state) {
   for (auto _ : state) {
-    for(int a = 0; a < 46; a++) {
-      for(int b = a + 1; b < 47; b++) {
-        for(int c = b + 1; c < 48; c++) {
-          for(int d = c + 1; d < 49; d++) {
-            for(int e = d + 1; e < 50; e++) {
-              for(int f = e + 1; f < 51; f++) {
-                for(int g = f + 1; g < 52; g++) {
+    for (int a = 0; a < 46; a++) {
+      for (int b = a + 1; b < 47; b++) {
+        for (int c = b + 1; c < 48; c++) {
+          for (int d = c + 1; d < 49; d++) {
+            for (int e = d + 1; e < 50; e++) {
+              for (int f = e + 1; f < 51; f++) {
+                for (int g = f + 1; g < 52; g++) {
                   EvaluateCards(a, b, c, d, e, f, g);
                 }
               }
@@ -67,30 +68,34 @@ BENCHMARK(EvaluateAllSevenCards);
 
 static unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
 static std::default_random_engine generator(seed);
-static std::uniform_int_distribution<int> distribution(0, 51);
 
-static std::vector<int> RandomCardSample(int size) {
-  std::vector<int> ret;
-  std::set<int> sample;
-
-  while (sample.size() < size) {
-    int number = distribution(generator);
-    if (sample.find(number) == sample.end()) {
-      ret.push_back(number);
-      sample.insert(number);
+class CardSampler {
+  std::array<int, 52> deck;
+public:
+  CardSampler(void) {
+    std::iota(deck.begin(), deck.end(), 0);
+  }
+  std::vector<int> sample(int size) {
+    std::vector<int> ret;
+    int residual_cards = deck.size();
+    for (int i = 0; i < size; i++) {
+      int target_index = generator() % residual_cards;
+      int tail_index = residual_cards - 1;
+      std::swap(deck[target_index], deck[tail_index]);
+      ret.push_back(deck[tail_index]);
+      residual_cards--;
     }
+    return ret;
   }
-
-  return ret;
-}
+};
 
 const int SIZE = 100;
 
 static void EvaluateRandomFiveCards(benchmark::State& state) {
   std::vector<std::vector<int>> hands;
-
+  CardSampler cs{};
   for (int i = 0; i < SIZE; i++) {
-    hands.push_back(RandomCardSample(5));
+    hands.push_back(cs.sample(5));
   }
   for (auto _ : state) {
     for (int i = 0; i < SIZE; i++) {
@@ -106,9 +111,10 @@ BENCHMARK(EvaluateRandomFiveCards);
 
 static void EvaluateRandomSixCards(benchmark::State& state) {
   std::vector<std::vector<int>> hands;
+  CardSampler cs{};
 
   for (int i = 0; i < SIZE; i++) {
-    hands.push_back(RandomCardSample(6));
+    hands.push_back(cs.sample(6));
   }
 
   for (auto _ : state) {
@@ -126,9 +132,10 @@ BENCHMARK(EvaluateRandomSixCards);
 
 static void EvaluateRandomSevenCards(benchmark::State& state) {
   std::vector<std::vector<int>> hands;
+  CardSampler cs{};
 
   for (int i = 0; i < SIZE; i++) {
-    hands.push_back(RandomCardSample(7));
+    hands.push_back(cs.sample(7));
   }
 
   for (auto _ : state) {
@@ -147,9 +154,10 @@ BENCHMARK(EvaluateRandomSevenCards);
 
 static void EvaluateRandomOmahaCards(benchmark::State& state) {
   std::vector<std::vector<int>> hands;
+  CardSampler cs{};
 
   for (int i = 0; i < SIZE; i++) {
-    hands.push_back(RandomCardSample(9));
+    hands.push_back(cs.sample(9));
   }
 
   for (auto _ : state) {
@@ -164,7 +172,8 @@ static void EvaluateRandomOmahaCards(benchmark::State& state) {
                          hands[i][7],
                          hands[i][8]);
     }
-  }}
+  }
+}
 BENCHMARK(EvaluateRandomOmahaCards);
 
 BENCHMARK_MAIN();