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diff --git a/challenge-005/paulo-custodio/cpp/ch-2.cpp b/challenge-005/paulo-custodio/cpp/ch-2.cpp
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+/*
+Challenge 005
+
+Challenge #2
+Write a program to find the sequence of characters that has the most anagrams.
+
+create a hash of all words in dictionary where key is sorted list of letters
+therefore two anagrams have the same key
+*/
+
+#include <algorithm>
+#include <cctype>
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <string>
+using namespace std;
+
+map<string, int> anagrams;
+
+void strtolower(string& str) {
+    for (size_t i = 0; i < str.size(); i++)
+        str[i] = tolower(str[i]);
+}
+
+void word_key(string& key, const string& word) {
+    key = word;
+    sort(key.begin(), key.end());
+}
+
+int main() {
+    int max_anagrams = 0;
+    string key, line;
+
+    ifstream ifs("words.txt");
+    if (!ifs.is_open()) return EXIT_FAILURE;
+
+    // collect anagram keys and count occurrences
+    while (getline(ifs, line)) {
+        strtolower(line);
+        word_key(key, line);
+
+        auto found = anagrams.find(key);
+        if (found == anagrams.end()) {
+            anagrams[key] = 1;
+
+            if (max_anagrams < 1)
+                max_anagrams = 1;
+        }
+        else {
+            found->second++;
+
+            if (max_anagrams < found->second)
+                max_anagrams = found->second;
+        }
+    }
+
+    // list anagrams
+    cout << "Maximum of " << max_anagrams << " anagrams" << endl;
+    for (auto& it : anagrams) {
+        if (it.second == max_anagrams)
+            cout << it.first << endl;
+    }
+
+    return EXIT_SUCCESS;
+}