#include struct node { int value; node* ptr; }; class OLL { public: OLL() { first = last = NewNode = NULL; } ~OLL() { destroy_list(); } void add_elem(int); void del_elem(int); void destroy_list(); node* min_elem(); private: node* first; node* last; node* NewNode; }; class stack { public: stack() { stack_top = NewNode = NULL; } ~stack() { destroy_stack(); } void push(int); void pop(); void destroy_stack(); int getMin(); private: node* stack_top; node* NewNode; OLL obj; }; void stack::push(int tempVal) { obj.add_elem(tempVal); NewNode = new node; NewNode->value = tempVal; if (stack_top == NULL) { stack_top = NewNode; stack_top->ptr = NULL; } else { NewNode->ptr = stack_top; stack_top = NewNode; } } void stack::pop() { node* temp = stack_top; obj.del_elem(stack_top->value); stack_top = stack_top->ptr; delete temp; } void stack::destroy_stack() { while (stack_top != NULL) pop(); NewNode = NULL; obj.destroy_list(); } int stack::getMin() { return obj.min_elem()->value; } void OLL::add_elem(int tempVal) { NewNode = new node; NewNode->value = tempVal; if (first == NULL) { first = NewNode; last = NewNode; first->ptr = NULL; } else if (tempVal <= first->value) { NewNode->ptr = first; first = NewNode; } else if (tempVal >= last->value) { last->ptr = NewNode; last = NewNode; last->ptr = NULL; } else { node* current = NULL; for (node* temp = first; temp != NULL; temp = temp->ptr) { if (tempVal < temp->value) { current->ptr = NewNode; NewNode->ptr = temp; break; } current = temp; } current = NULL; } } void OLL::del_elem(int tempVal) { node* current = NULL; if (tempVal == first->value) { current = first; first = first->ptr; delete current; } else { for (node* temp = first; temp != NULL; temp = temp->ptr) { if (temp->value == tempVal) { current->ptr = temp->ptr; delete temp; break; } current = temp; } } } void OLL::destroy_list() { node* temp = NULL; while (first != NULL) { temp = first; first = first->ptr; delete temp; } } node* OLL::min_elem() { return first; } int main() { stack obj; obj.push(16); obj.push(11); obj.push(15); obj.push(9); obj.push(10); obj.push(12); obj.push(8); obj.push(7); std::cout << obj.getMin() << " "; obj.pop(); std::cout << obj.getMin() << " "; obj.pop(); std::cout << obj.getMin(); return 0; }

Ace Code Challenge - Stack #2