[刷题] 多项式加法、乘法
作者：互联网
mooc例题
1 #include<stdio.h>
2 #include<malloc.h>
3 #include<string.h>
4 #include<time.h>
5 #include<math.h>
6
7 //指向结构体头节点的指针
8 typedef struct PolyNode *Polynomial;
9
10 struct PolyNode{
11 int coef;
12 int expon;
13 Polynomial link;
14 };
15
16 Polynomial ReadPoly();
17 void Attach(int c,int e,Polynomial *pRear);
18 Polynomial Add(Polynomial P1,Polynomial P2);
19 Polynomial Mult(Polynomial P1,Polynomial P2);
20 void PrintPoly(Polynomial P);
21
22 int main(){
23 Polynomial P1,P2,PP,PS;
24 P1 = ReadPoly();
25 P2 = ReadPoly();
26 PP = Mult(P1,P2);
27 PrintPoly(PP);
28 printf("\n");
29 PS = Add(P1,P2);
30 PrintPoly(PS);
31 return 0;
32 }
33
34 /*读入多项式*/
35 Polynomial ReadPoly(){
36 Polynomial P,Rear,t; /*Rear为指向当前结果尾项的指针*/
37 int c,e,N;
38 scanf("%d",&N);
39 P = (Polynomial)malloc(sizeof(struct PolyNode)); /*申请空节点*/
40 P->link = NULL;
41 Rear = P; /*初始化，Rear指向空节点*/
42 while(N--){
43 scanf("%d%d",&c,&e);
44 Attach(c,e,&Rear); /*增加一项*/
45 }
46 t = P;P = P->link;free(t); /*删除临时生成的头节点*/
47 return P;
48 }
49
50 /*插入新节点*/
51 /*更改Rear的值，传入指针*/
52 void Attach(int c,int e,Polynomial *pRear){
53 Polynomial P;
54 P = (Polynomial)malloc(sizeof(struct PolyNode));
55 P->coef = c;
56 P->expon = e;
57 P->link = NULL; /*Rear指向空节点*/
58 (*pRear)->link = P; /*pRear是指针的指针*/
59 *pRear = P; /*修改pRear的值*/
60 }
61
62 Polynomial Add(Polynomial P1,Polynomial P2){
63 Polynomial t1,t2,P,Rear,t;
64 t1 = P1;t2 = P2;
65 /*当生成新的头节点*/
66 P = (Polynomial)malloc(sizeof(struct PolyNode));
67 P -> link = NULL;
68 Rear = P;
69 /*当t1,t2都不空时，比较当前t1,t2的指数*/
70 while(t1 && t2){
71 if(t1->expon == t2->expon){
72 if(t1->coef + t2->coef){
73 Attach(t1->coef + t2->coef,t1->expon,&Rear);
74 }
75 t1 = t1->link;
76 t2 = t2->link;
77 }
78 else if(t1->expon > t2->expon){
79 Attach(t1->coef,t1->expon,&Rear);
80 t1 = t1->link;
81 }
82 else{
83 Attach(t2->coef,t2->expon,&Rear);
84 t2 = t2->link;
85 }
86 }
87 while(t1){
88 Attach(t1->coef,t1->expon,&Rear);
89 t1 = t1->link;
90 }
91 while(t2){
92 Attach(t2->coef,t2->expon,&Rear);
93 t2 = t2->link;
94 }
95 t = P;
96 P = P->link;
97 free(t);
98 return P;
99 }
100
101 Polynomial Mult(Polynomial P1, Polynomial P2)
102 {
103 Polynomial P, Rear;
104 Polynomial t1, t2, t;
105 if (!P1 ||!P2)
106 {
107 return NULL;
108
109 }
110 t1 = P1;
111 t2 = P2;
112 P = (Polynomial)malloc(sizeof(struct PolyNode));
113 Rear = P;
114 while (t2) /*用P1的第一项乘以P2，得到初始P*/
115 {
116 Attach(t1->coef*t2->coef, t1->expon + t2->expon, &Rear);
117 t2 = t2->link;
118 }
119 t1 = t1->link;
120
121 while (t1) /*t1的第一项后的每一项乘以t2的每一项*/
122 {
123 t2 = P2; /*每循环一遍要使指针回到首节点*/
124 Rear = P; /*将尾节点置到头结点*/
125 while (t2)
126 {
127 int c = t1->coef*t2->coef; /*以后每一项相乘的结果*/
128 int e = t1->expon + t2->expon;
129 while (Rear->link&&Rear->link->expon > e) /*找插入的位置*/
130 {
131 Rear = Rear->link;
132 }
133 if (Rear->link&&Rear->link->expon == e) /*相等就不需要申请一个新的节点，只要把系数相加*/
134 {
135 if (Rear->link->coef + c) /*判断系数是否为0*/
136 {
137 Rear->link->coef += c;
138 }
139 else /*系数和为0，删除节点*/
140 {
141 t = Rear->link;
142 Rear->link = t->link;
143 free(t);
144 }
145 }
146 else /*不相等，也就是小于的情况*/
147 {
148 t = (Polynomial)malloc(sizeof(struct PolyNode)); /*申请一个新的节点*/
149 t->link = NULL;
150 t->coef = c;
151 t->expon = e;
152 t->link = Rear->link;
153 Rear->link = t;
154 Rear = Rear->link;
155 }
156 t2 = t2->link;
157 }
158 t1 = t1->link;
159 }
160 /*把一开始申请的内容空P的指针删除，指向下一个位置*/
161 t2 = P;
162 P = P->link;
163 free(t2);
164 return P;
165 }
166
167 void PrintPoly(Polynomial P)
168 {
169 int flag = 0; /*辅助调整输出格式*/
170 if (!P)
171 {
172 printf("0 0");
173 return;
174 }
175 while (P)
176 {
177 if (!flag) /*可以看做系数 指数 ，空格 系数 指数，空格 系数 指数。。。。。。用flag标记第一次*/
178 {
179 flag = 1;
180
181 }
182 else /*不是第一项*/
183 {
184 printf(" ");
185 }
186 printf("%d %d", P->coef, P->expon);
187 P = P->link;
188 }
189 }
标签：多项式,t2,t1,link,加法,Polynomial,expon,Rear,刷题 来源： https://www.cnblogs.com/cxc1357/p/10633524.html