HDUOJ 1002 A + B Problem II

Problem Description

I have a very simple problem for you. Given two integers A and B, your job is to calculate the Sum of A + B.

Input

The first line of the input contains an integer T(1<=T<=20) which means the number of test cases. Then T lines follow, each line consists of two positive integers, A and B. Notice that the integers are very large, that means you should not process them by using 32-bit integer. You may assume the length of each integer will not exceed 1000.

Output

For each test case, you should output two lines. The first line is "Case #:", # means the number of the test case. The second line is the an equation "A + B = Sum", Sum means the result of A + B. Note there are some spaces int the equation. Output a blank line between two test cases.

Sample Input

2
1 2
112233445566778899 998877665544332211

Sample Output

Case 1:
1 + 2 = 3

Case 2:
112233445566778899 + 998877665544332211 = 1111111111111111110

大整數加法

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int MAX = 1009;
char a[MAX], b[MAX];
int num1[MAX], num2[MAX], ans[MAX];
int len_a, len_b;

void big_add()
{
    int carry = 0;
    int len = len_a > len_b ? len_a : len_b;

    for(int i = 0; i < len; i++)
    {
        int sum = num1[i] + num2[i] + carry;
        ans[i] = sum % 10;

        carry = sum / 10;
    }

    if(carry)
    {
        ans[len] = carry;
        len ++;
    }

    for(int i = len - 1; i >= 0; i--)
        printf("%d", ans[i]);
    printf("\n");
}

int main()
{
    int num, case_n;
    case_n = 1;
    scanf("%d", &num);
    while(num--)
    {
        memset(num1, 0, sizeof(num1));
        memset(num2, 0, sizeof(num2));

        scanf(" %s %s", a, b);

        len_a = strlen(a);
        len_b = strlen(b);

        int j = 0;
        for(int i = len_a - 1; i >= 0; i--)
            num1[j++] = a[i] - '0';

        j = 0;
        for(int i = len_b - 1; i >= 0; i--)
            num2[j++] = b[i] - '0';

        printf("Case %d:\n", case_n ++);

        printf("%s + %s = ", a, b);

        big_add();

        if(num)
            printf("\n");

    }
    return 0;
}

話說太久不刷題是不行啊，一個普通的大整數加法竟然都WA了好幾遍。。。