From 87a243ad3b121f663c33e27fa02b6793445392bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Borba?= <andre.borbaaf2b@gmail.com>
Date: Sat, 19 Sep 2026 09:25:20 -0300
Subject: [PATCH] =?UTF-8?q?=F0=9F=9F=A2=20Port=20problem=20242=20(Valid=20?=
 =?UTF-8?q?Anagram)=20from=20Swift=20to=20C++23?=
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Replaces swift/242.swift with solutions/0201-0300/0242-valid-anagram/,
keeping the general hash-map approach and adding a fixed 26-slot
count-array optimized version (valid given the problem's lowercase
English letters constraint).
---
 .../0201-0300/0242-valid-anagram/README.md    | 11 +++++
 .../0201-0300/0242-valid-anagram/solution.cpp | 44 +++++++++++++++++++
 .../0201-0300/0242-valid-anagram/solution.hpp | 15 +++++++
 .../0201-0300/0242-valid-anagram/test.cpp     | 13 ++++++
 swift/242.swift                               | 20 ---------
 5 files changed, 83 insertions(+), 20 deletions(-)
 create mode 100644 solutions/0201-0300/0242-valid-anagram/README.md
 create mode 100644 solutions/0201-0300/0242-valid-anagram/solution.cpp
 create mode 100644 solutions/0201-0300/0242-valid-anagram/solution.hpp
 create mode 100644 solutions/0201-0300/0242-valid-anagram/test.cpp
 delete mode 100644 swift/242.swift

diff --git a/solutions/0201-0300/0242-valid-anagram/README.md b/solutions/0201-0300/0242-valid-anagram/README.md
new file mode 100644
index 0000000..af07328
--- /dev/null
+++ b/solutions/0201-0300/0242-valid-anagram/README.md
@@ -0,0 +1,11 @@
+# 242. Valid Anagram
+
+[LeetCode problem 242](https://leetcode.com/problems/valid-anagram/)
+
+- **Difficulty**: Easy
+- **Tags**: hash-table, string, sorting
+
+## Description
+
+Given two strings `s` and `t`, return `true` if `t` is an anagram of `s`
+(uses the exact same letters, same counts), `false` otherwise.
diff --git a/solutions/0201-0300/0242-valid-anagram/solution.cpp b/solutions/0201-0300/0242-valid-anagram/solution.cpp
new file mode 100644
index 0000000..0ca4c8b
--- /dev/null
+++ b/solutions/0201-0300/0242-valid-anagram/solution.cpp
@@ -0,0 +1,44 @@
+#include "solution.hpp"
+
+#include <algorithm>
+#include <array>
+#include <unordered_map>
+
+namespace leetcode::p0242 {
+
+bool solve(const std::string& s, const std::string& t) {
+    if (s.size() != t.size()) {
+        return false;
+    }
+
+    std::array<int, 26> counts{};
+
+    for (char c : s) {
+        ++counts.at(static_cast<std::size_t>(c - 'a'));
+    }
+    for (char c : t) {
+        --counts.at(static_cast<std::size_t>(c - 'a'));
+    }
+
+    return std::ranges::all_of(counts, [](int count) { return count == 0; });
+}
+
+bool solveHashMap(const std::string& s, const std::string& t) {
+    if (s.size() != t.size()) {
+        return false;
+    }
+
+    std::unordered_map<char, int> countS;
+    std::unordered_map<char, int> countT;
+
+    for (char c : s) {
+        ++countS[c];
+    }
+    for (char c : t) {
+        ++countT[c];
+    }
+
+    return countS == countT;
+}
+
+} // namespace leetcode::p0242
diff --git a/solutions/0201-0300/0242-valid-anagram/solution.hpp b/solutions/0201-0300/0242-valid-anagram/solution.hpp
new file mode 100644
index 0000000..13a1894
--- /dev/null
+++ b/solutions/0201-0300/0242-valid-anagram/solution.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <string>
+
+namespace leetcode::p0242 {
+
+// optimized: O(n) time, O(1) space — fixed 26-slot count array (assumes
+// lowercase English letters, per the problem's constraints).
+bool solve(const std::string& s, const std::string& t);
+
+// hash-map: O(n) time, O(k) space (k = distinct characters) — works for any
+// character set, not just lowercase English letters.
+bool solveHashMap(const std::string& s, const std::string& t);
+
+} // namespace leetcode::p0242
diff --git a/solutions/0201-0300/0242-valid-anagram/test.cpp b/solutions/0201-0300/0242-valid-anagram/test.cpp
new file mode 100644
index 0000000..fbaf4ea
--- /dev/null
+++ b/solutions/0201-0300/0242-valid-anagram/test.cpp
@@ -0,0 +1,13 @@
+#include <catch2/catch_test_macros.hpp>
+
+#include "solution.hpp"
+
+TEST_CASE("Problem 242 - optimized", "[p0242]") {
+    CHECK(leetcode::p0242::solve("anagram", "nagaram"));
+    CHECK_FALSE(leetcode::p0242::solve("rat", "car"));
+}
+
+TEST_CASE("Problem 242 - hash map", "[p0242]") {
+    CHECK(leetcode::p0242::solveHashMap("anagram", "nagaram"));
+    CHECK_FALSE(leetcode::p0242::solveHashMap("rat", "car"));
+}
diff --git a/swift/242.swift b/swift/242.swift
deleted file mode 100644
index c074259..0000000
--- a/swift/242.swift
+++ /dev/null
@@ -1,20 +0,0 @@
-class Solution {
-    func isAnagram(_ s: String, _ t: String) -> Bool {
-        if s.count != t.count {
-            return false
-        }
-
-        var countS: [Character: Int] = [:]
-        var countT: [Character: Int] = [:]
-
-        for char in s {
-            countS[char, default: 0] += 1
-        }
-
-        for char in t {
-            countT[char, default: 0] += 1
-        }
-
-        return countS == countT
-    }
-}