From 2af9a81f28b567a40bf144481f67c7a30a2e6419 Mon Sep 17 00:00:00 2001
From: Sainnhe Park <sainnhe@gmail.com>
Date: Tue, 8 Mar 2022 15:54:17 +0800
Subject: [PATCH] Two Sum

---
 .gitignore             | 29 +++++++++++++++++++++--------
 CMakeLists.txt         | 38 ++++++++++++++++++++++++++++++++++++++
 include/s1_two_sum.hpp | 27 +++++++++++++++++++++++++++
 src/s1_two_sum.cpp     | 14 ++++++++++++++
 tests/s1_two_sum.cpp   | 31 +++++++++++++++++++++++++++++++
 5 files changed, 131 insertions(+), 8 deletions(-)
 create mode 100644 CMakeLists.txt
 create mode 100644 include/s1_two_sum.hpp
 create mode 100644 src/s1_two_sum.cpp
 create mode 100644 tests/s1_two_sum.cpp

diff --git a/.gitignore b/.gitignore
index 815e02a..a887e69 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,23 @@
-target
+.cache
+.cmake
+bin
+lib
+leetcode*
 
-# create by https://github.com/iamcco/coc-gitignore (Sun Jan 02 2022 18:30:21 GMT+0800 (China Standard Time))
-# Rust.gitignore:
-# Generated by Cargo
-# will have compiled files and executables
-/target/
+# create by https://github.com/iamcco/coc-gitignore (Tue Mar 08 2022 16:17:40 GMT+0800 (China Standard Time))
+# CMake.gitignore:
+CMakeLists.txt.user
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+_deps
 
-# These are backup files generated by rustfmt
-**/*.rs.bk
+# CMake.patch:
+# External projects
+*-prefix/
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..878b83b
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,38 @@
+cmake_minimum_required(VERSION 3.14)
+project(leetcode)
+
+# GoogleTest requires at least C++11
+set(CMAKE_CXX_STANDARD 11)
+
+include(FetchContent)
+FetchContent_Declare(
+  googletest
+  URL https://github.com/google/googletest/archive/refs/tags/release-1.11.0.zip
+)
+# For Windows: Prevent overriding the parent project's compiler/linker settings
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+FetchContent_MakeAvailable(googletest)
+
+enable_testing()
+
+FILE(GLOB Sources src/*.cpp)
+FILE(GLOB Tests tests/*.cpp)
+
+add_executable(
+  leetcode
+  ${Sources}
+  ${Tests}
+)
+target_link_libraries(
+  leetcode
+  gtest_main
+)
+
+include(GoogleTest)
+gtest_discover_tests(leetcode)
+
+target_include_directories(leetcode
+  PRIVATE
+    include
+)
+
diff --git a/include/s1_two_sum.hpp b/include/s1_two_sum.hpp
new file mode 100644
index 0000000..402dbe4
--- /dev/null
+++ b/include/s1_two_sum.hpp
@@ -0,0 +1,27 @@
+#ifndef S1_TWO_SUM_HPP
+#define S1_TWO_SUM_HPP
+
+#include <iostream>
+#include <unordered_map>
+#include <vector>
+
+class Solution {
+ public:
+  /**
+   * @brief Two Sum
+   *
+   * Given an array of integers `nums` and an integer `target`, return indices
+   * of the two numbers such that they add up to `target`.
+   *
+   * You may assume that each input would have **exactly one solution**, and you
+   * may not use the same element twice.
+   *
+   * You can return the answer in any order.
+   *
+   * @param nums the array of integers to be summed
+   * @param target the target integer
+   */
+  std::vector<int> twoSum(std::vector<int>& nums, int target);
+};
+
+#endif
diff --git a/src/s1_two_sum.cpp b/src/s1_two_sum.cpp
new file mode 100644
index 0000000..e043dd6
--- /dev/null
+++ b/src/s1_two_sum.cpp
@@ -0,0 +1,14 @@
+#include "s1_two_sum.hpp"
+using namespace std;
+
+vector<int> Solution::twoSum(vector<int>& nums, int target) {
+  unordered_map<int, int> hashtable;
+  for (int i = 0; i < nums.size(); ++i) {
+    auto it = hashtable.find(target - nums[i]);
+    if (it != hashtable.end()) {
+      return {it->second, i};
+    }
+    hashtable[nums[i]] = i;
+  }
+  return {};
+}
diff --git a/tests/s1_two_sum.cpp b/tests/s1_two_sum.cpp
new file mode 100644
index 0000000..cb3cdf9
--- /dev/null
+++ b/tests/s1_two_sum.cpp
@@ -0,0 +1,31 @@
+#include "s1_two_sum.hpp"
+
+#include <gtest/gtest.h>
+#include <vector>
+
+TEST(Problem1, Case1) {
+  std::vector<int> input1{ 2, 7, 11, 15 };
+  int input2{ 9 };
+  Solution solution;
+  std::vector<int> result = solution.twoSum(input1, input2);
+  std::vector<int> answer = std::vector<int>{ 0, 1 };
+  EXPECT_EQ(result, answer);
+}
+
+TEST(Problem1, Case2) {
+  std::vector<int> input1{ 3, 2, 4 };
+  int input2{ 6 };
+  Solution solution;
+  std::vector<int> result = solution.twoSum(input1, input2);
+  std::vector<int> answer = std::vector<int>{ 1, 2 };
+  EXPECT_EQ(result, answer);
+}
+
+TEST(Problem1, Case3) {
+  std::vector<int> input1{ 3, 3 };
+  int input2{ 6 };
+  Solution solution;
+  std::vector<int> result = solution.twoSum(input1, input2);
+  std::vector<int> answer = std::vector<int>{ 0, 1 };
+  EXPECT_EQ(result, answer);
+}