算法习题66：颠倒栈

颠倒栈。
题目:用递归颠倒一个栈。例如输入栈{1, 2, 3, 4, 5},1 在栈顶。
颠倒之后的栈为{5, 4, 3, 2, 1},5 处在栈顶。

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需要两中递归，一个是把底部元素找到，返回，然后最后压入，这样我们另一个递归从上至下，即可完成

注意要用引用，之前当成Java的写法，不用你引用，怎么改都不行，调试了才发现，引用和临时变量这种蛋疼的事

//============================================================================// Name        : ReverseStack.cpp// Author      : YLF// Version     :// Copyright   : Your copyright notice// Description : Hello World in C++, Ansi-style//============================================================================#include <iostream>#include <vector>using namespace std;class Stack{private:vector<int> stack;int size;public:Stack(){size=0;}~Stack(){}void Push(int va){stack.push_back(va);size++;}int Pop(){if(size == 0)return -1;int ret = stack.at(size-1);stack.pop_back();size--;return ret;}int Size(){return size;}bool isEmpty(){if(size == 0)return true;elsereturn false;}void Print(){int i = 0;for(i=stack.size()-1;i>=0;i--)cout<<"| "<<stack.at(i)<<" |"<<endl;cout<<"-----"<<endl;}};int BottomUp(Stack &stack);void ReverseStack(Stack &stack);int h(Stack &stack, int idx);int main() {Stack stack;int in;while(true){cin>>in;if(in != -1){stack.Push(in);}elsebreak;}stack.Print();ReverseStack(stack);stack.Print();return 0;}void ReverseStack(Stack &stack){if(stack.isEmpty()){cout<<"stack is empty!!";return;}int i = 0;int va=0;int size = stack.Size();for(i=0;i<size;i++){va = h(stack,i);stack.Push(va);}}/** * 改函数找到应该底朝天的那个元素返回 */int h(Stack &stack, int idx){int va = 0, cur = 0;if(idx == 0)return BottomUp(stack);else{cur = stack.Pop();va = h(stack,idx-1);stack.Push(va);return cur;}}/** * 返回最底下的元素 */int BottomUp(Stack &stack){int cur = stack.Pop();int ret = 0;if(stack.isEmpty())return cur;elseret = BottomUp(stack);stack.Push(cur);return ret;}

输出：

1 2 3 4 5 -1| 5 || 4 || 3 || 2 || 1 |-----| 1 || 2 || 3 || 4 || 5 |-----