Implemented RankTransformArray algorithm

CMakeLists.txt

@@ -61,6 +61,7 @@ target_sources(${PROJECT_NAME}
   ${PROJECT_SOURCE_DIR}/src/Array/Partition.cpp
   ${PROJECT_SOURCE_DIR}/src/Array/PlusOne.cpp
   ${PROJECT_SOURCE_DIR}/src/Array/RadixSort.cpp
+  ${PROJECT_SOURCE_DIR}/src/Array/RankTransformArray.cpp
   ${PROJECT_SOURCE_DIR}/src/Array/RemoveDuplicatesSortedArrayII.cpp
   ${PROJECT_SOURCE_DIR}/src/Array/RotateRight.cpp
   ${PROJECT_SOURCE_DIR}/src/Array/Search2DMatrix.cpp
@@ -228,6 +229,7 @@ add_executable(${PROJECT_NAME}_test
   ${PROJECT_SOURCE_DIR}/test/Array/testPartition.cpp
   ${PROJECT_SOURCE_DIR}/test/Array/testPlusOne.cpp
   ${PROJECT_SOURCE_DIR}/test/Array/testRadixSort.cpp
+  ${PROJECT_SOURCE_DIR}/test/Array/testRankTransformArray.cpp
   ${PROJECT_SOURCE_DIR}/test/Array/testRemoveDuplicatesSortedArrayII.cpp
   ${PROJECT_SOURCE_DIR}/test/Array/testRotateRight.cpp
   ${PROJECT_SOURCE_DIR}/test/Array/testSearch2DMatrix.cpp

benchmark/benchmarkTemplateTest.cpp

@@ -18,6 +18,7 @@
 #include <benchmark/benchmark.h>
 #include <algorithms/Array/CountSmallerAfterSelf.hpp>
 #include <algorithms/Array/DeckIncreasingReveal.hpp>
+#include <algorithms/Array/RankTransformArray.hpp>
 #include <algorithms/Array/ValidateStackSequences.hpp>
 #include <algorithms/BackTracking/BeautifulArrangement.hpp>
 #include <algorithms/BackTracking/NumbersConsecutiveDifferences.hpp>
@@ -102,5 +103,6 @@ GENERATE_BENCHMARK(PalindromePartitioningII,
 GENERATE_BENCHMARK(CountSmallerAfterSelf, SeqList<1024>());
 GENERATE_BENCHMARK(NextGreaterElementIII, 1999999999);
 GENERATE_BENCHMARK(ValidPalindrome, "A man, a plan, a canal: Panama");
+GENERATE_BENCHMARK(RankTransformArray, {37, 12, 28, 9, 100, 56, 80, 5, 12});
 
 }  // namespace algorithms::benchmark

docs/GenTable/ProblemsListTable.md

@@ -1,5 +1,5 @@
 # Problems List
-![Easy_counter](https://img.shields.io/badge/Easy-18-green.svg?style=for-the-badge&logo=c%2b%2b)
+![Easy_counter](https://img.shields.io/badge/Easy-19-green.svg?style=for-the-badge&logo=c%2b%2b)
 ![Medium_counter](https://img.shields.io/badge/Medium-94-yellow.svg?style=for-the-badge&logo=c%2b%2b)
 ![Hard_counter](https://img.shields.io/badge/Hard-15-red.svg?style=for-the-badge&logo=c%2b%2b)
 ![Undefined_counter](https://img.shields.io/badge/Undefined-36-lightgray.svg?style=for-the-badge&logo=c%2b%2b)
@@ -132,6 +132,7 @@
 | [Plus One](https://leetcode.com/problems/plus-one/description/) | ![Easy](https://img.shields.io/badge/Difficulty-Easy-green.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/src/Array/PlusOne.cpp) |
 | [Priority queue](https://en.wikipedia.org/wiki/Priority_queue) | ![Not Defined](https://img.shields.io/badge/Difficulty-ND-lightgray.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/include/algorithms/PriorityQueue/PriorityQueue.hpp) |
 | [Radix sort](https://en.wikipedia.org/wiki/Radix_sort) | ![Not Defined](https://img.shields.io/badge/Difficulty-ND-lightgray.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/src/Array/RadixSort.cpp) |
+| [Rank Transform of an Array](https://leetcode.com/problems/rank-transform-of-an-array/) | ![Easy](https://img.shields.io/badge/Difficulty-Easy-green.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/src/Array/RankTransformArray.cpp) |
 | [Reconstruct Itinerary](https://leetcode.com/problems/reconstruct-itinerary/) | ![Medium](https://img.shields.io/badge/Difficulty-Medium-yellow.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/src/Misc/FindItinerary.cpp) |
 | [Remove Duplicates]() | ![Not Defined](https://img.shields.io/badge/Difficulty-ND-lightgray.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/src/CTCI/Chapter2/RemoveDuplicates.cpp) |
 | [Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/) | ![Medium](https://img.shields.io/badge/Difficulty-Medium-yellow.svg) | [Source](https://github.com/BiagioFesta/algorithms/blob/master/src/Array/RemoveDuplicatesSortedArrayII.cpp) |

include/algorithms/Array/RankTransformArray.hpp

@@ -0,0 +1,40 @@
+/*
+  Copyright (C) 2020  Biagio Festa
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+#ifndef ALGORITHMS__ARRAY__RANKTRANSFORMARRAY__HPP
+#define ALGORITHMS__ARRAY__RANKTRANSFORMARRAY__HPP
+#include <algorithm>
+#include <vector>
+
+namespace algorithms {
+
+/*! \brief Given an array of integers arr, replace each element with its rank.
+ *  The rank represents how large the element is. The rank has the following
+ *  rules:
+ *    - Rank is an integer starting from 1.
+ *    - The larger the element, the larger the rank. If two elements are equal,
+ *      their rank must be the same.
+ *    - Rank should be as small as possible.
+ *
+ *  \note  Complexity  -->  Time: O(NlogN)  Space: O(N)
+ *  \note https://leetcode.com/problems/rank-transform-of-an-array/
+ */
+std::vector<int> RankTransformArray(const std::vector<int>& v);
+
+}  // namespace algorithms
+
+#endif  // ALGORITHMS__ARRAY__RANKTRANSFORMARRAY__HPP

src/Array/RankTransformArray.cpp

@@ -0,0 +1,46 @@
+/*
+  Copyright (C) 2020  Biagio Festa
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+#include <algorithm>
+#include <algorithms/Array/RankTransformArray.hpp>
+#include <vector>
+
+namespace algorithms {
+
+std::vector<int> RankTransformArray(const std::vector<int>& v) {
+  const std::size_t size = v.size();
+
+  std::vector<std::pair<int, std::size_t>> meta;
+  meta.reserve(size);
+  for (const int n : v) {  // O(N)
+    meta.emplace_back(n, meta.size());
+  }
+  std::sort(meta.begin(), meta.end());  // O(NlogN)
+
+  std::vector<int> rtn(size);
+  int counter = 1;
+  for (std::size_t i = 0; i < size; ++i) {  // O(N)
+    if (i > 0 && meta[i].first != meta[i - 1].first) {
+      ++counter;
+    }
+    rtn[meta[i].second] = counter;
+  }
+
+  return rtn;
+}
+
+}  // namespace algorithms

test/Array/testRankTransformArray.cpp

@@ -0,0 +1,37 @@
+/*
+  Copyright (C) 2020  Biagio Festa
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+#include <gtest/gtest.h>
+#include <algorithms/Array/RankTransformArray.hpp>
+#include <utility>
+#include <vector>
+
+namespace algorithms::test {
+
+TEST(Array, RankTransformArray) {
+  using Test = std::pair<std::vector<int>, std::vector<int>>;
+  const std::vector<Test> testCases = {
+      {{40, 10, 20, 30}, {4, 1, 2, 3}},
+      {{100, 100, 100}, {1, 1, 1}},
+      {{37, 12, 28, 9, 100, 56, 80, 5, 12}, {5, 3, 4, 2, 8, 6, 7, 1, 3}}};
+
+  for (const auto& [v, expt] : testCases) {
+    ASSERT_EQ(RankTransformArray(v), expt);
+  }
+}
+
+}  // namespace algorithms::test