Day 4 - Marina

exercise/01/containers.cpp

@@ -0,0 +1,66 @@
+#include "containers.h"
+#include <unordered_set>
+#include <sstream>
+//#include <algorithm>
+
+void remove_element(std::vector<int>& v, int index)
+{
+	v.erase(v.begin()+index);
+}
+
+void input_element(std::vector<std::wstring>& v, int index, const std::wstring& value)
+{
+	v.insert(v.begin() + index, value);
+}
+
+int list_nth_element(const std::list<int>& c, int index)
+{
+	auto it = c.begin();
+	std::advance(it, index);
+	return it != c.end() ? *it : 0;
+}
+
+void list_sort_desc(std::list<int>& c)
+{
+	c.sort(std::greater<int>());
+}
+
+int unique_numbers(std::wistream& wis)
+{
+	std::unordered_set<int> s;
+	int n;
+	while (wis >> n)
+		s.insert(n);
+	return s.size();
+}
+
+namespace
+{
+	std::wstring to_lower(const std::wstring& wstr)
+	{
+		std::wstring w(wstr);
+		for (wchar_t& wc : w)
+			 wc = ::towlower(wc);
+		//std::transform(w.begin(), w.end(), w.begin(), ::towlower);
+		return w;
+	}
+}
+
+word_frequency::word_frequency(std::wistream& wis)
+{
+	std::wstring w;
+	while (wis >> w)
+		word_freq[to_lower(w)]++;
+}
+
+int word_frequency::frequency(const std::wstring & s)
+{
+	const auto ws = to_lower(s);
+	const auto it = word_freq.find(ws);
+	return it != word_freq.end() ? it->second : 0;
+}
+
+int word_frequency::count()
+{
+	return word_freq.size();
+}

exercise/01/containers.h

@@ -2,6 +2,7 @@
 #include <string>
 #include <vector>
 #include <list>
+#include <map>
 
 void remove_element(std::vector<int>& v, int index);
 void input_element(std::vector<std::wstring>& v, int index, const std::wstring& value);
@@ -13,6 +14,7 @@ int unique_numbers(std::wistream&);
 
 class word_frequency
 {
+	std::map<std::wstring, int> word_freq;
 public:
 	word_frequency(std::wistream&);
 	int frequency(const std::wstring& s);

exercise/02/algorithms_test.cpp

@@ -8,6 +8,24 @@ using namespace Microsoft::VisualStudio::CppUnitTestFramework;
 #include <numeric>
 #include <chrono>
 
+namespace
+{
+bool is_vowel(wchar_t c)
+{
+	c = towlower(c);
+	return (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');
+}
+
+bool is_prime(int n)
+{
+	for (int i = 2; i <= n / 2; ++i)
+	{
+		if (n%i == 0)
+			return false;
+	}
+	return true;
+}
+}
 TEST_CLASS(test_standard_algorithms_usage)
 {
 public:
@@ -16,7 +34,7 @@ TEST_CLASS(test_standard_algorithms_usage)
 		std::wstringstream ss(L"14 -78 22");
 		std::vector<int> v;
 		// TODO: read values from input stream into vector
-
+		std::copy(std::istream_iterator<int, wchar_t>(ss), std::istream_iterator<int, wchar_t>(), std::back_inserter(v));
 		Assert::AreEqual(3u, v.size());
 		Assert::AreEqual(14, v[0]);
 		Assert::AreEqual(-78, v[1]);
@@ -27,6 +45,7 @@ TEST_CLASS(test_standard_algorithms_usage)
 	{
 		std::vector<int> v(10);
 		// TODO: fill vector with incremental values
+		std::iota(v.begin(), v.end(), 1);
 		Assert::AreEqual(10u, v.size());
 		Assert::IsTrue(std::is_sorted(v.cbegin(), v.cend()));
 		Assert::AreEqual( 1, v[0]);
@@ -37,6 +56,7 @@ TEST_CLASS(test_standard_algorithms_usage)
 		// generate
 		std::vector<int> v(10);
 		// TODO: fill vector with incremental values (by 2)
+		std::generate(v.begin(), v.end(), [n = -1]() mutable { return n += 2; });
 		Assert::IsTrue(std::is_sorted(v.cbegin(), v.cend()));
 		Assert::IsTrue(v.cend() == std::adjacent_find(v.cbegin(), v.cend(), [](int a, int b) { return b - a != 2;  }));
 		Assert::AreEqual(1, v[0]);
@@ -47,6 +67,7 @@ TEST_CLASS(test_standard_algorithms_usage)
 	{
 		std::vector<int> v = { 1, 5, 10 } ;
 		// TODO: change all values in a vector
+		std::transform(v.begin(), v.end(), v.begin(), [](int val) { return val * val * val; });
 		Assert::AreEqual(3u, v.size());
 		Assert::AreEqual(1, v[0]);
 		Assert::AreEqual(125, v[1]);
@@ -57,8 +78,8 @@ TEST_CLASS(test_standard_algorithms_usage)
 		int x[] = { 3, 5, 10 };
 		std::vector<int> y = { 4, 12, 10 };
 		std::vector<double> d;
-
 		// TODO: calculate distances from origin (from x and y collections) to new vector
+		std::transform(std::begin(x), std::end(x), y.begin(), std::back_inserter(d), [](int a, int b) { return sqrt(a*a + b * b); });
 		Assert::AreEqual(3u, d.size());
 		Assert::AreEqual(5., d[0]);
 		Assert::AreEqual(13., d[1]);
@@ -67,67 +88,74 @@ TEST_CLASS(test_standard_algorithms_usage)
 	TEST_METHOD(test_04a)
 	{
 		std::wstringstream ss(L"1.5 2.5 3.5");
-		auto res = // TODO: sum of all values in input stream
+		// TODO: sum of all values in input stream
+		auto res = std::accumulate(std::istream_iterator<double, wchar_t>(ss), std::istream_iterator<double, wchar_t>(), 0.0);
 		Assert::AreEqual(7.5, res);
 	}
 	TEST_METHOD(test_04b)
 	{
 		std::vector<std::wstring> v { L"A", L"V", L"L", L"!" };
-		auto res = // TODO: concatenated string with additional prefix 
+		// TODO: concatenated string with additional prefix 
+		auto res = std::accumulate(v.begin(), v.end(), std::wstring(L"GO "));
 		Assert::AreEqual(L"GO AVL!", res.c_str());
 	}
 	TEST_METHOD(test_04c)
 	{
 		struct person { std::wstring name; int age; };
 		std::vector<person> v{ {L"Pero", 33}, {L"Iva", 25} };
-		auto total_age = // TODO: sum of all ages
+		// TODO: sum of all ages
+		auto total_age = std::accumulate(v.begin(), v.end(), 0, [](const int& a, const person& p) { return a + p.age; });
 		Assert::AreEqual(58, total_age);
 	}
 
 	TEST_METHOD(test_05a)
 	{
 		std::vector<int> v { -5, 8, 11, 0, -9, 77, -4 };
-		auto number_of_negative = // TODO: 
+		auto number_of_negative = std::count_if(v.begin(), v.end(), [](int v) {return isless(v, 0); });
 		Assert::AreEqual(3, number_of_negative);
 	}
 	TEST_METHOD(test_05b)
 	{
 		std::vector<double> v { 1.5, 8, -11.23, 0, 1e10, 1e10, 1e10, 0, 99 };
-		auto number_of_invalid = // TODO: 
+		auto number_of_invalid = std::count(v.begin(), v.end(), 1e10);
 		Assert::AreEqual(3, number_of_invalid);
 	}
 	TEST_METHOD(test_05c)
 	{
 		struct point { int x, y; };
 		std::vector<point> v{ {1,1}, {-5,3}, {2,2}, {-7,-6}, {9,-4} };
-		auto number_in_first_quadrant = // TODO: 
+		auto number_in_first_quadrant = std::count_if(v.begin(), v.end(), [](point p) {return (p.x > 0 && p.y > 0); });
 		Assert::AreEqual(2, number_in_first_quadrant);
 	}
 
 	TEST_METHOD(test_06)
 	{
 		std::vector<int> v { 33, 16, 24, 41, 25, 19, 9 };
-		auto first_prime = // TODO: 
+		auto first_prime = *std::find_if(v.begin(), v.end(), is_prime);
 		Assert::AreEqual(41, first_prime);
 	}
 	TEST_METHOD(test_07a)
 	{
 		std::vector<double> v{ 1e10, 8, -11.23, 0, 1e10, 1e10, 1e10, 0, 99 };
 		// TODO: change every invalid value (1e10) with -1 
+		std::replace(v.begin(), v.end(), 1e10, -1.0);
 		Assert::AreEqual(-1., v[0]);
 		Assert::AreEqual(-1., v[4]);
 		Assert::AreEqual(-1., v[6]);
 	}
+
 	TEST_METHOD(test_07b)
 	{
 		std::wstring s(L"ponedjeljak");
 		// TODO: change every vowel with x 
+		std::replace_if(s.begin(), s.end(), is_vowel, 'x');
 		Assert::AreEqual(L"pxnxdjxljxk", s.c_str());
 	}
 	TEST_METHOD(test_08a)
 	{
 		std::vector<double> v{ 1e10, 8, -11.23, 0, 1e10, 1e10, 1e10, 0, 99 };
 		// TODO: delete all invalid values (1e10)
+		v.erase(std::remove(v.begin(), v.end(), 1e10), v.end());
 		Assert::AreEqual(5u, v.size());
 		Assert::AreEqual(8., v[0]);
 		Assert::AreEqual(99., v[4]);
@@ -137,18 +165,30 @@ TEST_CLASS(test_standard_algorithms_usage)
 	{
 		std::wstring s(L"ponedjeljak");
 		// TODO: delete all vowels 
+		s.erase(std::remove_if(s.begin(), s.end(), is_vowel), s.end());
 		Assert::AreEqual(L"pndjljk", s.c_str());
 	}
+
 	TEST_METHOD(test_09)
 	{
-		struct exam { std::wstring name; int points, grade; };
+		struct exam
+		{
+			std::wstring name; int points, grade; 
+			bool operator<(const exam& other)
+			{
+				return grade != other.grade ? grade < other.grade : points < other.points;
+			}
+		};
+
 		std::vector<exam> v{ {L"Pero", 55, 2}, {L"Iva", 93, 5}, {L"Marko", 89, 5} };
 		// TODO: sort vector by grade, then by points
+		std::sort(v.rbegin(), v.rend());
+		//std::sort(v.begin(), v.end(), [](const exam& l, const exam& r) { return l.grade != r.grade ? l.grade > r.grade : l.points > r.points; });
 		Assert::AreEqual(L"Iva", v[0].name.c_str());
 		Assert::AreEqual(L"Marko", v[1].name.c_str());
 		Assert::AreEqual(L"Pero", v[2].name.c_str());
-
 	}
+
 	TEST_METHOD(test_10a)
 	{
 		// nth_element
@@ -161,8 +201,10 @@ TEST_CLASS(test_standard_algorithms_usage)
 		std::random_shuffle(v.begin(), v.end());
 
 		using namespace std::chrono;
+		int half_size = v.size() / 2;
 		auto t1 = steady_clock::now();
 		// TODO: put median value in the middle of vector. fast.
+		std::nth_element(v.begin(), v.begin() + half_size, v.end());
 		auto t2 = steady_clock::now();
 		auto dur = duration_cast<milliseconds>(t2 - t1);
 		Assert::AreEqual(1000., v[v.size() / 2]); // median value
@@ -173,22 +215,24 @@ TEST_CLASS(test_standard_algorithms_usage)
 		struct employee { std::wstring name; int salary; };
 		std::vector<employee> v{ {L"Iva", 2000}, {L"Pero", 1000}, {L"Marko", 10000} };
 		// TODO: put employee with median salary in the middle of vector
+
 		std::nth_element(v.begin(), v.begin() + v.size() / 2, v.end(), [](const employee& a, const employee& b) { return a.salary < b.salary; });
 		Assert::AreEqual(L"Iva", v[v.size() / 2].name.c_str()); // median_salary
 	}
 	TEST_METHOD(test_12)
 	{
 		std::vector<double> v{ 11, 0.5, -97.23, -23.11, 48.78, 22.96, -77 };
-		auto smallest_value = // TODO: 
+		auto smallest_value = *std::min_element(v.begin(), v.end());
 		Assert::AreEqual(-97.23, smallest_value);
-		auto largest_value = // TODO: 
+		auto largest_value = *std::max_element(v.begin(), v.end());
 		Assert::AreEqual(48.78, largest_value);
 	}
 	TEST_METHOD(test_13)
 	{
 		std::vector<int> atp_points { 8445, 7480, 6220, 5300, 5285 };
 		// the most interesting match is the one with the smallest difference
-		auto smallest_difference = // TODO: 
+		std::adjacent_difference(atp_points.begin(), atp_points.end(), atp_points.begin(), [](const int x, const int y) {return abs(x - y); });
+		auto smallest_difference = *std::min_element(atp_points.begin(), atp_points.end());
 		Assert::AreEqual(15, smallest_difference);
 	}
 };