cpp: added "Backwards Read Primes" kata solution

Author: ProjectMutilation

cpp/codewars/backwardsReadPrimes.cpp

@@ -0,0 +1,37 @@
+// https://www.codewars.com/kata/5539fecef69c483c5a000015
+#include<cmath>
+#include <bits/stdc++.h>
+#include <string>
+class BackWardsPrime
+{
+public:
+  static std::string backwardsPrime(long long start, long long end){
+    std::string res;
+    bool prime, backwardsPrime, notSame;
+    const auto sep = " ";
+    for(auto i = start;i<=end;i++){
+      auto reversed_item =  reverse_item(i);
+      prime = isPrime(i);
+      backwardsPrime = isPrime(reversed_item);
+      notSame = i != reversed_item;
+      if(prime&&notSame&&backwardsPrime){
+       res += std::to_string(i) + sep; 
+      }
+    }
+    return res.substr(0,res.length()-1);
+  };
+  static long long reverse_item(long long item){
+   std::string s_item = std::to_string(item);
+   std::reverse(s_item.begin(),s_item.end());
+   return std::stoll(s_item);
+  }
+  static bool isPrime(long long item){
+    auto sq_root = std::sqrt(item); 
+    for(auto i = 2; i <= sq_root; i++){
+      if (item % i == 0) {
+         return false;
+      }
+    }
+    return true;
+  };
+};