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3_2.cpp
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3_2.cpp
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//
// 3_2.cpp
//
//
// Created by Pengyan Qin on 6/23/15.
//
//
#include <iostream>
#include <stack>
#include <cstdlib>
using namespace std;
const int SIZE = 100;
// using two array
// the problem is data redundancy
class minStack{
int a[SIZE];
int top; // current position
int minimum[SIZE];
public:
minStack(){
for(int i = 0; i < SIZE; ++i){
a[i] = 0;
minimum[i] = (1 << 30);
}
top = -1;
}
void push(int val){
if(top >= (SIZE-1)){
cout << "the stack is full!" << endl;
return;
}
a[++top] = val;
if(top == 0)
minimum[0] = val;
else
{
if(val < minimum[top-1])
minimum[top] = val;
else
minimum[top] = minimum[top - 1];
}
}
void pop(){
if(top == -1){
cout << "the stack is empty" << endl;
return;
}
--top;
}
int& front(){
if(top == -1){
cout << "the stack is empty" << endl;
exit(0);
}
return a[top];
}
int min(){
if(top == -1){
cout << "the stack is empty" << endl;
exit(0);
}
return minimum[top];
}
void print_elt(){
for(int i = 0; i <= top; ++i)
cout << a[i] << " ";
cout << endl;
}
void print_min(){
for(int i = 0; i <= top; ++i)
cout << minimum[i] << " ";
cout << endl;
}
};
//using an array to store elts
// using a stack to store the minimal element, size is small
class StackWithMin{
stack<int> minstack;
int a[SIZE];
int ntop;
public:
StackWithMin(){
for(int i = 0; i < SIZE; ++i){
a[i] = 0;
}
ntop = -1;
minstack.push((1<<30));
}
void push(int val){
if(ntop >= (SIZE-1)){
cout << "the stack is full!" << endl;
return;
}
a[++ntop] = val;
if(minstack.top() > val){
minstack.push(val);
}
else if(minstack.top() == val){
minstack.push(val);
}
}
void pop(){
if(ntop == -1){
cout << "the stack is empty" << endl;
return;
}
if(a[ntop] == minstack.top())
minstack.pop();
ntop--;
}
int& front(){
if(ntop == -1){
cout << "the stack is empty" << endl;
exit(0);
}
return a[ntop];
}
int min(){
return minstack.top();
}
void print_elt(){
for(int i = 0; i <= ntop; ++i)
cout << a[i] << " ";
cout << endl;
}
};
// using two stack, one is storing the elts
// another one is storing the smallest elts
class stackm{
stack<int> s1;
stack<int> s2;
public:
void push(int val){
s1.push(val);
if(s2.empty())
s2.push(val);
else{
if(val <= s2.top())
s2.push(val);
}
}
void pop(){
if(s1.top() == s2.top()){
s2.pop();
}
s1.pop();
}
int& top(){
return s1.top();
}
int min(){
return s2.top();
}
bool empty(){
return s1.empty();
}
};
int main(){
stackm ms;
ms.push(10);
ms.push(8);
ms.push(1);
ms.push(11);
ms.push(9);
ms.push(1);
ms.push(7);
ms.push(3);
// ms.print_elt();
cout << ms.min()<< endl;
ms.pop();
ms.pop();
ms.pop();
cout << ms.min()<< endl;
ms.pop();
ms.pop();
ms.pop();
cout << ms.min()<< endl;
ms.pop();
cout << ms.min()<< endl;
return 0;
}