[3sem] dsaa02 mod protecc and general fix

3sem/data structures and algos/02/program.cpp

@@ -6,6 +6,7 @@
 #include <chrono>
 #include <cmath>
 #include <cassert>
+#include <list>
 
 #ifdef DEBUG
 #define printf_d printf
@@ -20,12 +21,10 @@ private:
     int _capacity;
 
     void _resize(int new_size) {
-        int *new_container = new int [new_size];
-        for (int i = 0; i < this->_size; i++) {
-            *(new_container + i) = *(this->container + i);
-        }
-        std::swap(this->container, new_container);
-        delete [] new_container;
+        int *new_container = new int [new_size]{0};
+        std::copy(this->container, this->container + this->size(), new_container);
+        delete [] this->container;
+        this->container = new_container;
 
         this->_capacity = new_size;
     }
@@ -35,10 +34,8 @@ public:
         this->container = new int [this->_capacity]{0};
     }
     ~DynIntArr() {
-        if (this->container != nullptr) {
         delete [] this->container;
     }
-    }
 
     int &at(int pos) {
         if (pos < 0  || pos > this->_capacity) {
@@ -54,6 +51,20 @@ public:
         this->at(this->_size++) = val;
     }
 
+    void insert(int pos, int val) {
+        if (pos < 0  || pos > this->_capacity) {
+            throw std::runtime_error("Illegal array access");
+        }
+        if (this->_size+1 > this->_capacity) {
+            this->_resize(this->_capacity*2);
+        }
+        for (int i = this->size(); i > pos; i--) {
+            this->at(i) = this->at(i-1);
+        }
+        this->at(pos) = val;
+        this->_size += 1;
+    }
+
     int size() const {  // NOLINT(modernize-use-nodiscard)
         return this->_size;
     }
@@ -72,27 +83,31 @@ inline void time_passed(std::chrono::system_clock::time_point start, double &hol
 
 void algo_01(DynIntArr &cont);  // algo with my container
 void algo_02(std::vector<int> &cont);  // algo with stl's vector
+void algo_03(std::list<int> &cont);  // algo with stl's list
 
 
 // let's assume we are not including reading of data into algo's time
 // 'cause it can at worst be O(inf)
 int main() {
     int reserve = 50;
-    DynIntArr dyn_arr(reserve);
+    std::list<int> lst_int;
     std::vector<int> vec_int;
     vec_int.reserve(reserve);
+    DynIntArr dyn_arr(reserve);
 
     int N = 0;
     std::cout << "N=";
     std::cin >> N;
+    auto lit = lst_int.begin();
     for (int i = 0; i < N; i++) {
         int num = 0;
         std::cin >> num;
         dyn_arr.add(num);
         vec_int.push_back(num);
+        lst_int.push_back(num);
     }
 
-    double fft, sft = fft = 0;
+    double fft, sft, tft = sft = fft = 0;
 
     if (N <= 2) {  // Well, even if smth. is missed there is no way to determine
         goto endo;
@@ -108,10 +123,18 @@ int main() {
         algo_02(vec_int);
         time_passed(start, sft);
     }
+    {  // algo with stl's list
+        auto start = std::chrono::high_resolution_clock::now();
+        algo_03(lst_int);
+        time_passed(start, tft);
+    }
     {  // let's check integrity of content
         assert(dyn_arr.size() == vec_int.size());
+        assert(dyn_arr.size() == lst_int.size());
+        auto lit = lst_int.begin();
         for (int i = 0; i < dyn_arr.size(); i++) {
             assert(dyn_arr.at(i) == vec_int.at(i));
+            assert(dyn_arr.at(i) == *(lit++));
         }
     }
 
@@ -124,19 +147,24 @@ int main() {
     std::cout << std::endl;
 
     printf(
-            "algo_01 is %s than algo_02 by %.0f microseconds",
+            "algo_01 is %s than algo_02 by %.0f microseconds\n",
             (fft > sft? "slower" : "faster"), fabs(fft - sft)
     );
 
+    printf(
+            "algo_01 is %s than algo_03 by %.0f microseconds\n",
+            (fft > tft? "slower" : "faster"), fabs(fft - tft)
+    );
+
     return 0;
 }
 
 void algo_01(DynIntArr &cont) {
-    if (cont.size() <= 2) {  // See this_file:97
+    if (cont.size() <= 2) {  // See this_file:112
         return;
     }
 
-    int step = (cont.at(cont.size()-1) - cont.at(0)) / (cont.size() - 1);
+    int step = (cont.at(cont.size()-1) - cont.at(0)) / (cont.size());
     int miss_pos = -1;
     for (int i = 1; i < cont.size(); i++) {
         int p = cont.at(i - 1),
@@ -149,21 +177,17 @@ void algo_01(DynIntArr &cont) {
     }
 
     if (miss_pos != -1) {
-        int val = cont.at(0) - step;
-        int elc = cont.size() + 1;
-        cont = DynIntArr(cont.size() + 1);
-        for (int i = 0; i < elc; i++) {
-            cont.add(val += step);
-        }
+        int val = cont.at(miss_pos) - step;
+        cont.insert(miss_pos, val);
     }
 }
 
 void algo_02(std::vector<int> &cont) {
-    if (cont.size() <= 2) {  // See this_file:97
+    if (cont.size() <= 2) {  // See this_file:112
         return;
     }
 
-    int step = (cont.at(cont.size()-1) - cont.at(0)) / (cont.size() - 1);
+    int step = (cont.at(cont.size()-1) - cont.at(0)) / (cont.size());
     int miss_pos = -1;
     for (int i = 1; i < cont.size(); i++) {
         int p = cont.at(i - 1),
@@ -176,12 +200,36 @@ void algo_02(std::vector<int> &cont) {
     }
 
     if (miss_pos != -1) {
-        int val = cont.at(0) - step;
-        int elc = cont.size() + 1;
-        cont.clear();
-        for (int i = 0; i < elc; i++) {
-            cont.push_back(val += step);
+        auto vit = cont.begin();
+        std::advance(vit, miss_pos);
+        cont.insert(vit, *vit - step);
     }
+}
+
+void algo_03(std::list<int> &cont) {
+    if (cont.size() <= 2) {  // See this_file:112
+        return;
+    }
+
+    int step = (cont.back() - cont.front()) / (cont.size());
+    int miss_pos = -1;
+    {
+        auto lit = cont.begin();
+        for (int i = 1; i < cont.size(); i++) {
+            int p = *lit++,
+                    c = *(lit);
+
+            if (c - p != step) {
+                miss_pos = i;
+                break;
+            }
+        }
+    }
+
+    if (miss_pos != -1) {
+        auto lit = cont.begin();
+        std::advance(lit, miss_pos);
+        cont.insert(lit, *lit - step);
     }
 }