本文主要是介绍烙饼排序,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
问题:
#include<iostream>
#include<cassert>
using namespace std;
class CPrefixSorting
{private:int* m_CakeArray;//烙饼信息数组int m_nCakeCnt;//烙饼个数 int m_nMaxSwap;//最多翻转次数,即上界 int* m_SwapArray;//交换结果数组,即保存最优解的每一步交换 int* m_ReverseCakeArray; //当前翻转烙饼信息数组 int* m_ReverseCakeArraySwap;//当前翻转烙饼交换结果数组 int m_nSearch;//当前遍历次数信息 public:CPrefixSorting(){m_nCakeCnt=0;m_nMaxSwap=0;} void Run(int *pCakeArray,int nCakeCnt){Init(pCakeArray,nCakeCnt);m_nSearch=0;Search(0);}void Init(int* pCakeArray,int nCakeCnt){assert(pCakeArray!=NULL);assert(nCakeCnt>0);m_nCakeCnt=nCakeCnt;m_CakeArray=new int[m_nCakeCnt];assert(m_CakeArray!=NULL);for(int i=0;i<m_nCakeCnt;i++){m_CakeArray[i]=pCakeArray[i];}m_nMaxSwap=UpBound(m_nCakeCnt);m_SwapArray=new int[m_nMaxSwap];assert(m_SwapArray!=NULL);m_ReverseCakeArray=new int[m_nCakeCnt];for(int i=0;i<m_nCakeCnt;i++){m_ReverseCakeArray[i]=m_CakeArray[i];}m_ReverseCakeArraySwap=new int[m_nMaxSwap];}int UpBound(int nCakeCnt){return (nCakeCnt-1)*2;}int LowerBound(int* pCakeArray,int nCakeCnt){int t,ret=0;for(int i=1;i<nCakeCnt;i++){t=pCakeArray[i]-pCakeArray[i-1];if(t==1 || t==-1){}else{ret++;}}if (ret==0 && pCakeArray[nCakeCnt-1] != nCakeCnt-1)ret++;return ret;}void Search(int step){int i,nEstimate;m_nSearch++;nEstimate=LowerBound(m_ReverseCakeArray,m_nCakeCnt);if(step+nEstimate>=m_nMaxSwap)return;if(IsSorted(m_ReverseCakeArray,m_nCakeCnt)){if(step<m_nMaxSwap){m_nMaxSwap=step;for(i=0;i<m_nMaxSwap;i++)m_SwapArray[i]=m_ReverseCakeArraySwap[i];}return;}for(i=1;i<m_nCakeCnt;i++){Revert(0,i);m_ReverseCakeArraySwap[step]=i;Search(step+1);Revert(0,i);}}bool IsSorted(int* pCakeArray,int nCakeCnt){for(int i=1;i<nCakeCnt;i++){if(pCakeArray[i-1]>pCakeArray[i]){return false;}}return true;}void Revert(int nBegin,int nEnd){assert(nEnd>nBegin);int i,j,t;for(i=nBegin,j=nEnd;i<j;i++,j--){t=m_ReverseCakeArray[i];m_ReverseCakeArray[i]=m_ReverseCakeArray[j];m_ReverseCakeArray[j]=t;}}void Output(){for (int i = 0; i < m_nMaxSwap; i++) printf("%d\n", m_SwapArray[i]); printf("Search Times : %d\n", m_nSearch); printf("Total Swap times = %d\n", m_nMaxSwap); }
};
int main()
{int a[] = {3, 2, 1, 6, 5, 4, 9, 8, 7, 0}; CPrefixSorting test; test.Run(a, 10); test.Output(); system("pause"); return 0;
}
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