64 lines
925 B
C++
64 lines
925 B
C++
#ifndef _STACK_HPP_
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#define _STACK_HPP_
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#include <iostream>
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template <class T>
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class Stack
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{
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private:
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T *_v;
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int _len = 10;
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int _used = 0;
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public:
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Stack()
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{
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_v = new T[_len];
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}
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void push(T const &elem)
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{
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_v[_used++] = elem;
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expand();
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}
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T pop() { return !_used ? NULL : _v[--_used]; }
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T top() const { return !_used ? NULL : _v[_used - 1]; }
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bool empty() { return _used ? false : true; }
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int depth() { return _used; };
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protected:
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void expand()
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{
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if (((double)_used / (double)_len) <= 0.75)
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return;
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_len = _len * 2;
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T *p = new T[_len];
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for (int i = 0; i <= _used; i++)
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p[i] = _v[i];
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delete[] _v;
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_v = p;
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}
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void shrink()
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{
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if (((double)_used / (double)_len) >= 0.25)
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return;
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_len = _len >> 1;
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T *p = new T[_len];
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for (int i = 0; i <= _used; i++)
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p[i] = _v[i];
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delete[] _v;
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_v = p;
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}
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};
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#endif |