堆栈、队列中求最大值

#include <iostream>#include <vector>#include <cstdlib>#include <cassert>#include <time.h>#include <queue>#include <algorithm>#include <Windows.h>using namespace std;#define TEST_QUEUEtemplate<typename T>class StackMax{public:StackMax(){}const T& Max(){assert(!Empty());return s[maxIndex()];}void Push(const T& Val){s.push_back(Val);if (maxListIndex.empty() || Val > s[maxIndex()]){maxListIndex.push_back(s.size()-1);}}const T& Top(){assert(!Empty());return s.back();}void Pop(){assert(!Empty());if (maxIndex() == s.size()-1){maxListIndex.pop_back();}s.pop_back();}bool Empty(){return s.empty();}unsigned Size(){return s.size();}private:unsigned maxIndex(){return maxListIndex.back();}private:vector<T> s;//the element index in s,the last is the largest onevector<unsigned> maxListIndex;};template<typename T>class QueueMax{public:QueueMax(){}bool Empty(){return (s1.Empty() && s2.Empty());}void Push(const T& Val){s2.Push(Val);}const T&Top(){assert(!Empty());if (s1.Empty()){while(!s2.Empty()){s1.Push(s2.Top());s2.Pop();}}return s1.Top();}void Pop(){assert(!Empty());if (s1.Empty()){while(!s2.Empty()){s1.Push(s2.Top());s2.Pop();}}s1.Pop();}unsigned Size(){return s1.Size()+s2.Size();}const T&Max(){assert(!Empty());if (!s1.Empty()){if (!s2.Empty() && s2.Max() > s1.Max()){s2.Max();}elsereturn s1.Max();}elsereturn s2.Max();}private:StackMax<T> s1,s2;};int main(){srand(time(0));#ifndef TEST_QUEUEStackMax<int> sm;vector<int> vi;DWORD tSm=0,tVi=0;for (int i=0;i<5000;i++){if (rand()%3!=0){int r=rand();sm.Push(r);vi.push_back(r);}else{if (!sm.Empty()){sm.Pop();vi.pop_back();}}if (!sm.Empty()){assert(sm.Top() == vi.back());DWORD t1=GetTickCount();int m1=sm.Max();DWORD t2=GetTickCount();int m2=1<<31;for (int k=0;k<vi.size();k++)m2=max(m2,vi[k]);DWORD t3=GetTickCount();assert(m1==m2);cout << m1 << '/t' << m2 << endl;tSm+=(t2-t1);tVi+=(t3-t2);}assert(vi.size() == sm.Size());cout << vi.size() << endl;}while(!sm.Empty()){assert(sm.Top() == vi.back());int m1=sm.Max();int m2=1<<31;for (int k=0;k<vi.size();k++)m2=max(m2,vi[k]);assert(m1==m2);cout << m1 << '/t' << m2 << endl;sm.Pop();vi.pop_back();}assert(vi.empty());cout << tSm << '/t' << tVi << endl;#elseQueueMax<int> q;q.Push(3);q.Push(10);q.Push(1);q.Push(6);q.Push(2);q.Push(9);while(!q.Empty()){cout << q.Max() << endl;q.Pop();}#endifsystem("pause");return 0;}

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