Factorial trailing zeroes (#202)

* add factorial trailing zeroes

* impl factorial trailing zeroes

leetcode-cc/FactorialTrailingZeroes.hpp

@@ -0,0 +1,38 @@
+#include <stack>
+
+#include "TestHelper.h"
+#include "problem.h"
+#include "solution.h"
+
+using namespace std;
+
+IMPLEMENT_PROBLEM_CLASS(
+    PFactorialTrailingZeroes, 172, DIFFI_MEDIUM, TOPIC_ALGORITHMS,
+    "Factorial Trailing Zeroes",
+    "Given an integer n, return the number of trailing zeroes in n!.",
+    {"Math"});
+
+class SFactorialTrailingZeroes : public ISolution {
+ public:
+  size_t problemId() const override { return 172; }
+  string name() const override {
+    return ("Solution for " + string("Factorial Trailing Zeroes"));
+  }
+  string location() const override { return __FILE_NAME__; }
+  int test() const override {
+    return testHelper<int, int>(
+        {3, 5, 0, 6, 18}, {0, 1, 0, 1, 3},
+        [this](auto input) { return this->trailingZeroes(input); });
+  };
+  int benchmark() const override { return 0; }
+
+ private:
+  int trailingZeroes(int n) const {
+    int count = 0;
+    while (n > 0) {
+      count += n / 5;
+      n /= 5;
+    }
+    return count;
+  }
+};

leetcode-cc/FractionToDecimal.hpp

@@ -11,7 +11,7 @@ IMPLEMENT_PROBLEM_CLASS(
     "Fraction to Recurring Decimal",
     "Given two integers representing the numerator and denominator of a "
     "fraction, return the fraction in string format.",
-    {""});
+    {"Math"});
 
 class SFractionToDecimal : public ISolution {
  public:

runtime-cc/src/registration.cc

@@ -24,6 +24,7 @@
 #include "../leetcode-cc/EvaluateReversePolishNotation.hpp"
 #include "../leetcode-cc/ExcelSheetColNum.hpp"
 #include "../leetcode-cc/ExcelSheetColTitle.hpp"
+#include "../leetcode-cc/FactorialTrailingZeroes.hpp"
 #include "../leetcode-cc/FindMinInRotatedSortedArray.hpp"
 #include "../leetcode-cc/FindMinInRotatedSortedArrayII.hpp"
 #include "../leetcode-cc/FindPeakElement.hpp"
@@ -743,5 +744,12 @@ const int registerAll(std::shared_ptr<Container> handle) {
   handle->registerSolution(
       []() -> ArcSolution { return std::make_shared<SExcelSheetColNum>(); });
 
+  handle->registerProblem([]() -> ArcProblem {
+    return std::make_shared<PFactorialTrailingZeroes>();
+  });
+  handle->registerSolution([]() -> ArcSolution {
+    return std::make_shared<SFactorialTrailingZeroes>();
+  });
+
   return 0;
 }