bzoj3767 A+B Problem加强版

#include<cstdio>
#include<cstring>
#define N 10000010
int a[N],b[N],c[N],l1,l2,l3;
char ch1[N],ch2[N];
bool m1,m2;
inline int max(int a,int b){return a>b?a:b;}
int main()
{
    scanf("%s",ch1+1);l1=strlen(ch1+1);
    scanf("%s",ch2+1);l2=strlen(ch2+1);
    if (ch1[1]==‘-‘){l1--;m1=1;}
    if (ch2[1]==‘-‘){l2--;m2=1;}
    for (int i=1;i<=l1;i++)a[i]=ch1[l1-i+1+m1]-‘0‘;
    while (!a[l1]&&l1>1)l1--;
    if (l1==1&&!a[1])m1=0;
    for (int i=1;i<=l2;i++)b[i]=ch2[l2-i+1+m2]-‘0‘;
    while (!b[l2]&&l2>1)l2--;
    if (l2==1&&!b[1])m2=0;
    l3=max(l1,l2);
    if (m1^m2)
    {
        if (m1)
        {
            for (int i=1;i<=l3;i++)
            {
                int t=a[i];
                a[i]=b[i];
                b[i]=t;
            }
            int t=l1;l1=l2;l2=t;
        }
        bool mrk=0;
        if (l2>l1)mrk=1;
        else if (l1==l2)
        {
            for (int i=l1;i>=1;i--)
                if (a[i]<b[i]){mrk=1;break;}
                else if (a[i]>b[i])break;
        }
        if (mrk)
        {
            printf("-");
            for (int i=1;i<=l3;i++)
            {
                int t=a[i];
                a[i]=b[i];
                b[i]=t;
            }
            int t=l1;l1=l2;l2=t;
             
        }
        for (int i=1;i<=l3;i++)
        {
            a[i]-=b[i];
            if (a[i]<0)
            {
                a[i]+=10;
                int p=i+1;
                while (a[p]==0)
                {
                    a[p]=9;
                    p++;
                }
                a[p]--;
            }
        }
        while (l3>1&&!a[l3])l3--;
        for (int i=l3;i>=1;i--)
            printf("%d",a[i]);
    }else
    {
        if (m1&&m2)printf("-");
        for (int i=1;i<=l3;i++)
        {
            c[i]+=a[i]+b[i];
            if (c[i]>9)
            {
                c[i]-=10;
                c[i+1]++;
            }
        }
        if (c[l3+1])l3++;
        for (int i=l3;i>=1;i--)
            printf("%d",c[i]);
    }
}