diff --git a/2017/puzzle-04-01.cc b/2017/puzzle-04-01.cc
new file mode 100644
index 0000000..ab0af27
--- /dev/null
+++ b/2017/puzzle-04-01.cc
@@ -0,0 +1,37 @@
+#include <iostream>
+#include <string>
+#include <vector>
+
+auto split(std::string const& line, char c) -> std::vector<std::string>
+{
+  std::vector<std::string> result;
+  std::size_t idx{0};
+  while (idx != std::string::npos) {
+    auto next{line.find(c, idx)};
+    if (next == std::string::npos) {
+      result.push_back(line.substr(idx));
+      idx = next;
+    }
+    else {
+      result.push_back(line.substr(idx, next - idx));
+      idx = next + 1;
+    }
+  }
+  return result;
+}
+
+auto main() -> int
+{
+  std::string line;
+  unsigned valid{0};
+  while (std::getline(std::cin, line) && !line.empty()) {
+    std::vector<std::string> words{split(line, ' ')};
+    std::sort(words.begin(), words.end());
+    if (std::adjacent_find(words.begin(), words.end()) == words.end()) {
+      ++valid;
+    }
+  }
+
+  std::cout << "Valid passphrases: " << valid << '\n';
+  return 0;
+}
diff --git a/2017/puzzle-04-02.cc b/2017/puzzle-04-02.cc
new file mode 100644
index 0000000..1015df2
--- /dev/null
+++ b/2017/puzzle-04-02.cc
@@ -0,0 +1,40 @@
+#include <iostream>
+#include <string>
+#include <vector>
+
+auto split(std::string const& line, char c) -> std::vector<std::string>
+{
+  std::vector<std::string> result;
+  std::size_t idx{0};
+  while (idx != std::string::npos) {
+    auto next{line.find(c, idx)};
+    if (next == std::string::npos) {
+      result.push_back(line.substr(idx));
+      idx = next;
+    }
+    else {
+      result.push_back(line.substr(idx, next - idx));
+      idx = next + 1;
+    }
+  }
+  return result;
+}
+
+auto main() -> int
+{
+  std::string line;
+  unsigned valid{0};
+  while (std::getline(std::cin, line) && !line.empty()) {
+    std::vector<std::string> words{split(line, ' ')};
+    for (auto& w : words) {
+      std::sort(w.begin(), w.end());
+    }
+    std::sort(words.begin(), words.end());
+    if (std::adjacent_find(words.begin(), words.end()) == words.end()) {
+      ++valid;
+    }
+  }
+
+  std::cout << "Valid passphrases: " << valid << '\n';
+  return 0;
+}