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* Finding no. of digits in a Number * Initialize n * Initialize n as int * Changes done * Changes done with codes by adding more comments * Changes done with codes by adding name as md * Modified comments * add void * remove void & update comments * Set some changes to pass Awesome CI Workflow * add return 0 & file name in lower case * Changes done.. * Update finding_number_of_Digits_in_a_Number.cpp * Update finding_number_of_Digits_in_a_Number.cpp * Update finding_number_of_Digits_in_a_Number.cpp * formatting filenames0ec45e33* updating DIRECTORY.md * clang-format and clang-tidy fixes for0ec45e33* clang-format and clang-tidy fixes for9c0a437e* updating DIRECTORY.md * Wrote test, needs review * [fix/docs]: Fix tests/code and add documentation Co-authored-by: David Leal <halfpacho@gmail.com> Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
112 lines
3.2 KiB
C++
112 lines
3.2 KiB
C++
/**
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* @file
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* @brief Implementation of the [DNF
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* sort](https://www.geeksforgeeks.org/sort-an-array-of-0s-1s-and-2s/)
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* implementation
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* @details
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* C++ program to sort an array with 0, 1 and 2 in a single pass(DNF sort).
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* Since one traversal of the array is there hence it works in O(n) time
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* complexity.
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* @author [Sujal Gupta](https://github.com/heysujal)
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*/
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#include <algorithm> /// for std::is_sorted
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#include <cassert> /// for assert
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#include <iostream> /// for std::swap and io operations
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#include <vector> /// for std::vector
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/**
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* @namespace sorting
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* @breif Sorting algorithms
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*/
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namespace sorting {
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/**
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* @namespace dnf_sort
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* @brief Functions for the [DNF
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* sort](https://en.wikipedia.org/wiki/Dutch_national_flag_problem)
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* implementation
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*/
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namespace dnf_sort {
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/**
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* @brief The main function implements DNF sort
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* @tparam T type of array
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* @param a array to be sorted,
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* @param arr_size size of array
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* @returns void
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*/
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template <typename T>
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std::vector<T> dnfSort(const std::vector<T> &in_arr) {
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std::vector<T> arr(in_arr);
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uint64_t lo = 0;
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uint64_t hi = arr.size() - 1;
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uint64_t mid = 0;
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// Iterate till all the elements
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// are sorted
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while (mid <= hi) {
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switch (arr[mid]) {
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// If the element is 0
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case 0:
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std::swap(arr[lo++], arr[mid++]);
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break;
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// If the element is 1 .
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case 1:
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mid++;
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break;
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// If the element is 2
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case 2:
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std::swap(arr[mid], arr[hi--]);
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break;
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}
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}
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return arr;
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}
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} // namespace dnf_sort
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} // namespace sorting
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/**
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* @brief Self-test implementations
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* @returns void
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*/
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static void test() {
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// 1st test
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// [1, 0, 2, 1] return [0, 1, 1, 2]
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std::vector<uint64_t> array1 = {0, 1, 1, 2};
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std::cout << "Test 1... ";
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std::vector<uint64_t> arr1 = sorting::dnf_sort::dnfSort(array1);
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assert(std::is_sorted(std::begin(arr1), std::end(arr1)));
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std::cout << "passed" << std::endl;
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// 2nd test
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// [1, 0, 0, 1, 1, 0, 2, 1] return [0, 0, 0, 1, 1, 1, 1, 2]
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std::vector<uint64_t> array2 = {1, 0, 0, 1, 1, 0, 2, 1};
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std::cout << "Test 2... ";
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std::vector<uint64_t> arr2 = sorting::dnf_sort::dnfSort(array2);
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assert(std::is_sorted(std::begin(arr2), std::end(arr2)));
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std::cout << "passed" << std::endl;
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// 3rd test
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// [1, 1, 0, 0, 1, 2, 2, 0, 2, 1] return [0, 0, 0, 1, 1, 1, 1, 2, 2, 2]
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std::vector<uint64_t> array3 = {1, 1, 0, 0, 1, 2, 2, 0, 2, 1};
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std::cout << "Test 3... ";
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std::vector<uint64_t> arr3 = sorting::dnf_sort::dnfSort(array3);
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assert(std::is_sorted(std::begin(arr3), std::end(arr3)));
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std::cout << "passed" << std::endl;
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// 4th test
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// [2, 2, 2, 0, 0, 1, 1] return [0, 0, 1, 1, 2, 2, 2]
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std::vector<uint64_t> array4 = {2, 2, 2, 0, 0, 1, 1};
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std::cout << "Test 4... ";
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std::vector<uint64_t> arr4 = sorting::dnf_sort::dnfSort(array4);
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assert(std::is_sorted(std::begin(arr4), std::end(arr4)));
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std::cout << "passed" << std::endl;
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}
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/**
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* @brief Main function
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* @returns 0 on exit
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*/
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int main() {
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test(); // execute the test
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return 0;
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}
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