1074. 宇宙無敵加法器(20)

//幾個坑點：1.最後一個判例是輸出1個0的情況，注意判斷輸出0的個數 2.最後有進位的時候，final的位數要加1 

//PAT-1-1074
#include <iostream>
#include <algorithm>
#include <string>
#include <math.h>
#include <sstream>
#include <vector>
using namespace std;

int main(){
    string decimal;
    
    string a,b,res;
    res="";
    cin>>decimal>>a>>b;
    
    int count=0;
    int l0=decimal.length(),la=a.length(),lb=b.length();
    
    int sum=0,carry=0;
    //vector<int> res;
    while (count<min(la,lb)) {
        count++;
        int di;
        if (l0-count>=0) {
            di = decimal[l0-count]-'0'==0?10:decimal[l0-count]-'0';
        }else di = 10;
       
        sum = (a[la-count]+b[lb-count]-'0'-'0'+carry)%(di);
        carry=a[la-count]+b[lb-count]-'0'-'0'+carry>=(di)?1:0;
        char c=sum+'0';
        res+=c;
    }
    while (count<la) {
        count++;
        int di;
        if (l0-count>=0) {
            di = decimal[l0-count]-'0'==0?10:decimal[l0-count]-'0';
        }else di = 10;
        sum = (a[la-count]-'0'+carry)%(di);
        
        carry=a[la-count]-'0'+carry>=(di)?1:0;
        char c=sum+'0';
        res+=c;
    }
    while (count<lb) {
        count++;
        int di;
        if (l0-count>=0) {
            di = decimal[l0-count]-'0'==0?10:decimal[l0-count]-'0';
        }else di = 10;
        
        sum = (b[lb-count]-'0'+carry)%(di);
        carry=b[lb-count]-'0'+carry>=(di)?1:0;
        char c=sum+'0';
        res+=c;
    }
    string final="";
    int finaldigit=0;
    if (carry==1) {
        res+='1';
        finaldigit =max(la, lb)+1;
    }else finaldigit = max(la, lb);
    
    for (int i=0; i<finaldigit; i++) {
        final+=res[res.length()-i-1];
    }
    int begin=final.length();
    for (int i=0; i<final.length(); i++) {
        if (final[i]=='0') {
            continue;
        }else {
            begin = i;
            break;
        }
    }
    if (begin==final.length()) {
        cout<<"0";
    }
    else {
        
        for (int i=begin; i<final.length(); i++) {
            cout<<final[i];
        }
    }
    return 0;
}