#include <stdio.h>
#include <stdlib.h>
#define DUMMY -1

void output_P(int P[], int size);
void Padd(int A[], int B[], int C[]);
char compare(int a, int b);

void output_P(int P[], int size) {
    int i;
    int first = 1;
    for (i = 2; i < size; i += 2) {
        if (P[i+1] != 0) {
            if (!first) {
                printf(" + ");
            }
            if (P[i] > 1) {
                printf("%dx^%d", P[i+1], P[i]);
            } else if (P[i] == 1) {
                printf("%dx", P[i+1]);
            } else {
                printf("%d", P[i+1]);
            }
            first = 0;
        }
    }
    if (first) {  // 如果多項式為0
        printf("0");
    }
    printf("\n");
}

void Padd(int A[], int B[], int C[]) {
    int i = 2, j = 2, k = 2;
    int sizeA = A[1], sizeB = B[1];
    while (i < sizeA * 2 + 2 || j < sizeB * 2 + 2) {
        if (i >= sizeA * 2 + 2) {
            C[k] = B[j];
            C[k+1] = B[j+1];
            j += 2;
        } else if (j >= sizeB * 2 + 2) {
            C[k] = A[i];
            C[k+1] = A[i+1];
            i += 2;
        } else if (A[i] > B[j]) {
            C[k] = A[i];
            C[k+1] = A[i+1];
            i += 2;
        } else if (A[i] < B[j]) {
            C[k] = B[j];
            C[k+1] = B[j+1];
            j += 2;
        } else {
            C[k] = A[i];
            C[k+1] = A[i+1] + B[j+1];
            if (C[k+1] == 0) {
                k -= 2;  // 如果係數為0，不添加這一項
            }
            i += 2;
            j += 2;
        }
        k += 2;
    }
    C[1] = (k - 2) / 2;
    C[0] = DUMMY;
    printf("A: ");
    output_P(A, sizeA * 2 + 2);
    printf("B: ");
    output_P(B, sizeB * 2 + 2);
    printf("C = A + B: ");
    output_P(C, k);
}

char compare(int a, int b) {
    if (a > b) return '>';
    if (a < b) return '<';
    return '=';
}

int main() {
    int A[] = { DUMMY, 4, 4, 5, 3, 2, 2, 3, 0, 2 };
    int B[] = { DUMMY, 3, 3, 6, 1, 5, 0, 1 };
    int C[13] = { DUMMY };
    
    Padd(A, B, C);
    return 0;
}