Exercise 5, Sheet 1

mainEx5.cpp

@@ -0,0 +1,94 @@
+#include <iostream>
+#include <vector>
+#include <list>
+#include <algorithm>     // for lower_bound and is_sorted
+#include <random>        // for random number generation
+#include <chrono>        // for timing
+using namespace std;
+
+void insertIntoVector(vector<int>& vec, int n)
+{
+    minstd_rand generator; 
+    uniform_int_distribution<int> distribution(1, n);
+
+    for (int i = 0; i < n; ++i)
+    {
+        int value = distribution(generator);
+        auto position = lower_bound(vec.begin(), vec.end(), value);
+        vec.insert(position, value);
+    }
+    if (!is_sorted(vec.begin(), vec.end()))
+        cout << "Warning: Vector is not sorted!\n";
+}
+
+void insertIntoList(list<int>& lst, int n)
+{
+    minstd_rand generator;
+    uniform_int_distribution<int> distribution(1, n);
+    for (int i = 0; i < n; ++i)
+    {
+        int value = distribution(generator);
+        auto position = find_if(lst.begin(), lst.end(),
+                                [value](int x){ return x >= value; });
+        lst.insert(position, value);
+    }
+    vector<int> tmp(lst.begin(), lst.end());
+    if (!is_sorted(tmp.begin(), tmp.end()))
+        cout << "Warning: List is not sorted!\n";
+}
+
+double measureVector(int n)
+{
+    vector<int> vec(n);
+    for (int i = 0; i < n; ++i)
+        vec[i] = i + 1;
+
+    auto start = chrono::high_resolution_clock::now();
+    insertIntoVector(vec, n);
+    auto end = chrono::high_resolution_clock::now();
+    chrono::duration<double> elapsed = end - start;
+
+    cout << "Vector final size: " << vec.size()
+         << ", is_sorted: " << boolalpha
+         << is_sorted(vec.begin(), vec.end()) << endl;
+
+    return elapsed.count();
+}
+
+double measureList(int n)
+{
+    list<int> lst;
+    for (int i = 1; i <= n; ++i)
+        lst.push_back(i);
+
+    auto start = chrono::high_resolution_clock::now();
+    insertIntoList(lst, n);
+    auto end = chrono::high_resolution_clock::now();
+    chrono::duration<double> elapsed = end - start;
+
+    vector<int> tmp(lst.begin(), lst.end());
+    cout << "List final size:   " << lst.size()
+         << ", is_sorted: " << boolalpha
+         << is_sorted(tmp.begin(), tmp.end()) << endl;
+
+    return elapsed.count();
+}
+
+int main()
+{
+    int testSizes[] = {1000, 5000, 10000};
+
+    for (int i = 0; i < 3; ++i)
+    {
+        int n = testSizes[i];
+        cout << "--- n = " << n << " ---" << endl;
+
+        double timeVec = measureVector(n);
+        double timeList = measureList(n);
+
+        cout << "Vector time: " << timeVec << " seconds" << endl;
+        cout << "List time:   " << timeList << " seconds" << endl;
+        cout << endl;
+    }
+    return 0;
+}