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单链表实现多项式相乘，有这样的一个思路可以参考：
实现多项式相乘，最关键的是系数和指数的两个数据，这里命名为coef和HighPower。
最简便的办法是使用两个嵌套循环例如(3x^2+4x^1)(x^2+2x^4)用3x^2遍历另外一个括号内的数据，同时实现本身括号内的遍历。
这个想法的核心程序可归纳为以下：
while(pList!=NULL){ while(pList2!=NULL){ pNew=(PNODE)malloc(sizeof(NODE)); pNew->pNext=NULL; pNew->coef=(pList->coef)*(pList2->coef); pNew->HighPower=(pList->HighPower)+(pList2->HighPower); pReslut=addNewItem(pReslut,pNew); pList2=pList2->pNext; } pList2=pHead2; pList=pList->pNext; }
这样即可实现将所有数据，输出到一个新的链表里面。
但同时这也带来了不少问题，怎样才能合并新的链表里面相同系数的参数呢？
这里可以使用这样的方法：
创捷一个新表New,新表New2，将原有的表拆分循环复制在NEW2，然后将NEW2复制给NEW,如果在NEW中有相同项，则直接相加或者相乘，如果没有，则在链表最后添加新的节点。这样即可实现合并单链表中相同系数的参数。
源码如下：
#include<stdio.h> #include<stdlib.h> typedef struct node{ int coef; int HighPower; struct node *pNext; }NODE,*PNODE; PNODE crateList(); void traverseLinkList(PNODE); PNODE caculate(PNODE,PNODE); PNODE addNewItem(PNODE ,PNODE ); PNODE total(PNODE); PNODE ListFind(PNODE,PNODE); int main(){ PNODE pList,pList2,pNew; pList=crateList(); getchar(); pList2=crateList(); pNew=caculate(pList,pList2); pNew=total(pNew); traverseLinkList(pNew); return(0); } PNODE crateList(){ int a,b,c; PNODE pCurrent,pPre,pHead=NULL; pCurrent=NULL;pPre=NULL; b=0,c=0; while(1){ if(scanf("%d %d",&b,&c)!=2) break; pCurrent=(PNODE)malloc(sizeof(NODE)); if(pHead==NULL) pHead=pCurrent; else pPre->pNext=pCurrent; pCurrent->pNext=NULL; pCurrent->coef=b; pCurrent->HighPower=c; pPre=pCurrent; } puts("input end,now next step"); return(pHead); } void traverseLinkList(PNODE pList){ PNODE pCurrent; pCurrent=pList; if(pCurrent==NULL) puts("No Data Record"); else while(pCurrent!=NULL){ printf("the Coef is %d,and HighPower is %d\n",pCurrent->coef,pCurrent->HighPower); pCurrent=pCurrent->pNext; } } PNODE caculate(PNODE pList,PNODE pList2){ PNODE pNew,pCurrent,pPre,pHead2=pList2,pReslut=NULL; if(!pList||!pList2){ puts("wrong!"); return(0); } while(pList!=NULL){ while(pList2!=NULL){ pNew=(PNODE)malloc(sizeof(NODE)); pNew->pNext=NULL; pNew->coef=(pList->coef)*(pList2->coef); pNew->HighPower=(pList->HighPower)+(pList2->HighPower); pReslut=addNewItem(pReslut,pNew); pList2=pList2->pNext; } pList2=pHead2; pList=pList->pNext; } return(pReslut); } PNODE addNewItem(PNODE pReslut,PNODE pAdd){ PNODE pHead=NULL,pCurrent; if(pReslut==NULL){ return(pAdd); } pHead=pReslut; pCurrent=pReslut; while(pCurrent->pNext!=NULL) pCurrent= pCurrent->pNext; pCurrent->pNext=pAdd; pAdd->pNext=NULL; return(pHead); } PNODE total(PNODE pNew){ PNODE pNew3,pCurrent,pPre,pHead,pNew2=NULL; pCurrent=pNew; if(!pNew) return(0); pNew3=(PNODE)malloc(sizeof(NODE)); pNew2=(PNODE)malloc(sizeof(NODE)); pNew3->pNext=NULL; while(pCurrent!=NULL){ pNew3->coef=pCurrent->coef; pNew3->HighPower=pCurrent->HighPower; pNew2=ListFind(pNew2,pNew3); if(!pHead) pHead=pNew; pCurrent=pCurrent->pNext; } return(pHead); } PNODE ListFind(PNODE pNew,PNODE pList){ PNODE pCurrent,pPre,pHead,pCurrent2; while(pCurrent!=NULL){ if(pCurrent->HighPower==pList->HighPower){ pCurrent->coef=(pCurrent->coef)*(pList->coef); pCurrent->HighPower=pCurrent->HighPower+pList->HighPower; return(pHead); } pCurrent=pCurrent->pNext; } pCurrent=(PNODE)malloc(sizeof(NODE)); if(!pHead) pHead=pCurrent; else pPre->pNext=pCurrent; puts("ok"); pCurrent->pNext=NULL; pCurrent->coef=pList->coef; pCurrent->HighPower=pList->HighPower; pPre=pCurrent; return(pHead); }
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原文地址：http://www.cnblogs.com/hakase/p/5858154.html
