HDU-1002 A + B Problem II

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 515227    Accepted Submission(s): 98635

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

 

解题思路：

如果同学们会Java的话，就可以直接用大数进行计算

 

但是练习一下C++的大数加法还是挺好的

这道题C++不能直接进行大数的加法，所以我采用string数组来进行辅助计算，会比较简单一些

利用string的相关函数进行操作会比较便捷

还有就是一些加法上的小细节了，注意进位之类的，从后往前加，然后还要注意有没有加完

 

代码如下：

#include<bits/stdc++.h>
#define mem(a) memset(a,0,sizeof(a))
#define forn(i,n) for(int i=0;i<n;++i)
#define for1(i,n) for(int i=1;i<=n;++i)
#define IO std::ios::sync_with_stdio(false); std::cin.tie(0)
using namespace std;
typedef long long ll;
const int maxn=1e3+5;
const int mod=10007;
const int inf=0x3f3f3f3f;

ll n,m,t,k;
string num1,num2;

string add(string stra,string strb)
{
    string res;
    string str1=stra;
    string str2=strb;
    reverse(str1.begin(),str1.end());
    reverse(str2.begin(),str2.end());
    int i=0;
    int x=0;
    while(i<str1.size()&&i<str2.size())
    {
        int a=str1[i]-'0';
        int b=str2[i]-'0';
        int c=a+b+x;
        x=c/10;
        c=c%10;
        char s='0'+c;
        res=s+res;
        i++;
    }
    if(i<str1.size())
    {
        while(i<str1.size())
        {
            str1[i]=str1[i]+x;
            int w=str1[i]-'0';
            x=w/10;
            w=w%10;
            str1[i]='0'+w;
            res=str1[i]+res;
            i++;
        }
    }
    if(i<str2.size())
    {
        while(i<str2.size())
        {
            str2[i]=str2[i]+x;
            int w=str2[i]-'0';
            x=w/10;
            w=w%10;
            str2[i]='0'+w;
            res=str2[i]+res;
            i++;
        }
    }
    if(x==1)
    {
        char cc='1';
        res=cc+res;
    }
    return res;
}

int main()
{
    IO;
    cin>>m;
    int k=1;
    while(k<=m)
    {
        if(k!=1)
            cout<<endl;
        cin>>num1>>num2;
        string ans=add(num1,num2);
        cout<<"Case "<<k<<":"<<endl;
        cout<<num1<<" + "<<num2<<" = "<<ans<<endl;
        k++;
    }
    return 0;
}