1 files changed, 56 insertions, 0 deletions
diff --git a/store/works/solutions/leetcode/cpp/17.cpp b/store/works/solutions/leetcode/cpp/17.cpp
new file mode 100644
index 0000000..74e33b4
--- /dev/null
+++ b/store/works/solutions/leetcode/cpp/17.cpp
@@ -0,0 +1,56 @@
+#include <string>
+#include <vector>
+
+using std::string;
+using std::vector;
+
+vector<char> c_map[9]{
+    {'a', 'b', 'c'},
+    {'d', 'e', 'f'},
+    {'g', 'h', 'i'},
+    {'j', 'k', 'l'},
+    {'m', 'n', 'o'},
+    {'p', 'q', 'r', 's'},
+    {'t', 'u', 'v'},
+    {'w', 'x', 'y', 'z'}};
+
+void combine(const string::const_iterator &current, const string::const_iterator &end, string &head, vector<string> &result)
+{
+    const auto &chars = c_map[(*current) - '2'];
+
+    if (current == end)
+    {
+        for (auto c : chars)
+        {
+            head.push_back(c);
+            result.push_back(head);
+            head.pop_back();
+        }
+        return;
+    }
+
+    for (auto c : chars)
+    {
+        head.push_back(c);
+        combine(current + 1, end, head, result);
+        head.pop_back();
+    }
+}
+
+class Solution
+{
+public:
+    vector<string> letterCombinations(string digits)
+    {
+        std::vector<string> result;
+
+        if (digits.empty())
+            return result;
+
+        std::string head;
+
+        combine(digits.cbegin(), digits.cend() - 1, head, result);
+
+        return result;
+    }
+};