merge lists

.\polynomial_combine.c

# include <stdio.h>
# include <stdlib.h>

typedef struct Node{
	int coeff;
	int exp;
	struct Node *next;
} node;

void append(node **head, int coeff, int exp){
	node *new_node = (node *)malloc(sizeof(node));
	new_node->coeff = coeff;
	new_node->exp = exp;
	new_node->next = NULL;
	if(*head==NULL){
		*head=new_node;
		return;
	}
	node *tmp=*head;

	while(tmp->next != NULL)
		tmp = tmp->next;
	tmp->next=new_node;
}

void combine(node **p){
	for (node *i=*p;i != NULL; i=i->next){
		for(node *j=i; j->next != NULL; ){
			if(i->exp == j->next->exp){
				i->coeff += j->next->coeff;
				node *dup = j->next;
				j->next = j->next->next;
				free(dup);
			}
			else{
				j=j->next;
			}
		}
	} 
}
void print_polynomial(node *head){
	if(head == NULL){
		printf("0\n");
		return;
	}
	while(head != NULL){
		printf("%dx^%d", head->coeff, head->exp);
		if(head -> next != NULL)
			printf(" + ");
		head=head->next;
	}
	printf("\n");
}
int main(){
	node *p=NULL;
	int n;
	scanf("%d", &n);
	for(int i=0; i<n; i++){
		int exp, coeff;
		scanf(" %d %d", &coeff, &exp);
		append(&p, coeff, exp);
	}
	print_polynomial(p);
	combine(&p);
	print_polynomial(p);


}