bzoj1754 [Usaco2005 qua]Bull Math

题目

深夜水题第二弹，高精度乘法。

论三分钟打完。。

#include<bits/stdc++.h>char s1[101],s2[101];int l1,l2,l3;int a[101],b[101],c[101];int main(){    freopen("in.txt","r",stdin);    gets(s1),gets(s2);    while (s1[l1]>='0'&&s1[l1]<='9')l1++;    while (s2[l2]>='0'&&s2[l2]<='9')l2++;    for (int i=1;i<=l1;i++)a[l1-i+1]=s1[i-1]-'0';    while (!a[l1])l1--;    for (int i=1;i<=l2;i++)b[l2-i+1]=s2[i-1]-'0';    while (!b[l2])l2--;    for (int i=1;i<=l1;i++)      for (int j=1;j<=l2;j++)        c[i+j-1]+=a[i]*b[j];    for (int i=1;i<=l1+l2+2;i++)        while (c[i]>9)            c[i]-=10,c[i+1]++;    for (l3=l1+l2+3;l3;l3--)if (c[l3]) break;    for (int i=l3;i>=1;i--)printf("%d",c[i]);    return 0;}