Merge remote-tracking branch 'upstream/master'

1 files changed, 55 insertions, 0 deletions

diff --git a/challenge-238/deadmarshal/cpp/ch-2.cpp b/challenge-238/deadmarshal/cpp/ch-2.cpp
new file mode 100644
index 0000000000..e2c00022aa
--- /dev/null
+++ b/challenge-238/deadmarshal/cpp/ch-2.cpp
@@ -0,0 +1,55 @@
+#include<iostream>
+#include<vector>
+#include<algorithm>
+
+template<typename T>
+T product(T n)
+{
+  T prod = 1;
+  while(n)
+  {
+    prod *= n % 10;
+    n /= 10;
+  }
+  return prod;
+}
+
+template<typename T>
+T helper(T n)
+{
+  T sum = 0;
+  while(n >= 10)
+  {
+    sum++;
+    n = product<T>(n);
+  }
+  return sum;
+}
+
+template<typename T>
+void persistence_sort(std::vector<T>& v)
+{
+  std::sort(v.begin(),v.end(),[](T a, T b){
+    T ha = helper<T>(a), hb = helper<T>(b);
+    return ha == hb ? a < b : ha < hb;
+  });
+}
+
+template<typename T>
+std::ostream &operator<<(std::ostream &os,
+			 const std::vector<T>& vec)
+{
+  for(const auto &e : vec) os << e << ' ';
+  os << "\n";
+  return os;
+}
+
+int main()
+{
+  std::vector<int> vec1{15,99,1,34},vec2{50,25,33,22};
+  persistence_sort(vec1);
+  persistence_sort(vec2);
+  std::cout << vec1 << vec2;
+  return 0;
+}
+