Large Number Template

 1 struct BigNum{ 2         #define maxlen 1000 3         #define memc(a, b) memcpy(a, b, sizeof(b)) 4         #define mem0(a) memset(a, 0, sizeof(a)) 5         typedef __int64 Num[maxlen + 2]; 6         Num num; 7         BigNum operator+(BigNum num2) { 8                 BigNum ans; 9                 mem0(ans.num);10                 for(int i = 1; i <= maxlen; i++) {11                         ans.num[i] += num[i] + num2.num[i];12                         ans.num[i + 1] += ans.num[i] / (int)1e9;13                         ans.num[i] %= (int)1e9;14                 }15                 return ans;16         }17         BigNum operator*(BigNum num2) {18                 BigNum ans;19                 mem0(ans.num);20                 for(int i = 1; i <= maxlen; i++) {21                         for(int j = 1; j <= maxlen; j++) {22                                 if(i + j - 1 <= maxlen) {23                                         ans.num[i + j - 1] += num[i] * num2.num[j];24                                         ans.num[i + j] += ans.num[i + j - 1] / (int)1e9;25                                         ans.num[i + j - 1] %= (int)1e9;26                                 }27                         }28                 }29                 return ans;30         }31         void inp() {32                 char s[maxlen + 2];33                 mem0(num);34                 scanf("%s", s);35                 int len = strlen(s), cnt = 0;36                 for(int i = len - 1; i >= 0; i -= 9) {37                         int p = 0, x = 0, t = 1;38                         while(i - p >= 0 && p < 9) {39                                 x += t * (s[i - p] - ‘0‘);40                                 p++;41                                 t *= 10;42                         }43                         num[++cnt] = x;44                 }45         }46         void outp() {47                 int p = 1;48                 for(int i = maxlen; i >= 1; i--) {49                         if(num[i]) {50                                 p = i;51                                 break;52                         }53                 }54                 cout<< num[p];55                 while(--p) {56                         int a[9] = {0}, x = num[p];57                         for(int i = 0; i < 9; i++) {58                                 a[i] = x % 10;59                                 x /= 10;60                         }61                         for(int i = 8; i >= 0; i--) {62                                 printf("%d", a[i]);63                         }64                 }65         }66 };

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Large Number Template