62 lines
1.2 KiB
C++
62 lines
1.2 KiB
C++
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//string + *
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#include<iostream>
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using namespace std;
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string operator *(string a,string b)
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{
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string c;
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int al=a.length(),bl=b.length(),cl=0;
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int *ci;
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ci=new int[al+bl+5];
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for(int i=0;i<(al+bl+5);i++)ci[i]=0;
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for(int i=0;i<al;i++) a[i]=a[i]-48;
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for(int i=0;i<bl;i++) b[i]=b[i]-48;
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for(int j=0;j<bl;j++)
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for(int i=0;i<al;i++)
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ci[i+j]+=a[al-i-1]*b[bl-j-1];
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for(int i=0;i<(al+bl+3);i++)
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{
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ci[i+1]+=ci[i]/10;
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ci[i]%=10;
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if(ci[i+1]!=0)cl=i+1;
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}
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c.resize(cl+1);
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for(int i=0;i<=cl;i++)
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c[i]=ci[cl-i]+48;
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delete []ci;
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return c;
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}
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string operator+(string a,string b)
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{
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string c;
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int al=a.length(),bl=b.length(),cl=0;
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int l=al>bl?al:bl;
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c.resize(l+3);
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for(int i=0;i<al;i++)a[i]=a[i]-48;//string转int
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for(int i=0;i<bl;i++)b[i]=b[i]-48;
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for(int i=0;i<(l+3);i++)c[i]=0;//c初始化
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for(int i=0;i<l;i++)//加法计算核心
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{
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if((al-i-1)>=0)c[i]=a[al-i-1]+c[i];
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if((bl-i-1)>=0)c[i]=b[bl-i-1]+c[i];
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}
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for(int i=0;i<(l+2);i++)//处理进位
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{
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c[i+1]+=c[i]/10;
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if(c[i+1]!=0)cl=i+1;
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c[i]=c[i]%10+48;
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}
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if(c[cl]<10)c[cl]+=48;
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char t; //c反转
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for(int i=0;i<=cl/2;i++){t=c[i];c[i]=c[cl-i];c[cl-i]=t;}
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c.resize(cl+1);
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return c;
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}
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int main()
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{
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string a,b;
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cin>>a>>b;
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cout<<a*b;
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return 0;
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}
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