ACM模板

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#include<string>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
struct bign
{int d[200010], len;bign() { memset(d, 0, sizeof d); len = 1; }bign(int num) { *this = num; }bign(char* num) { *this = num; }bign operator=(const char* num){len = strlen(num);for (int i = 0; i < len; i++) d[i] = num[len - i - 1] - '0';return *this;}bign operator=(int num){char c[1010];sprintf(c, "%d", num);*this = c;return *this;}void clear(){while (len > 1 && !d[len - 1]) len--;}bign operator+(const bign& b){bign c; c.len = 0;for (int i = 0, t = 0; t || i < len || i < b.len; i++){if (i < len) t += d[i];if (i < b.len) t += b.d[i];c.d[c.len++] = t % 10;t /= 10;}return c;}bign operator-(const bign& b){bign c; c.len = 0;for (int i = 0, t = 0; i < len; i++){t += d[i];if (i < b.len) t -= b.d[i];c.d[c.len++] = (t + 10) % 10;if (t >= 0) t = 0;else t = -1;}c.clear();return c;}bign operator*(const bign& b){bign c; c.len = len + b.len;for (int i = 0; i < len; i++) for (int j = 0; j < b.len; j++) c.d[i + j] += d[i] * b.d[j];for (int i = 0; i < c.len - 1; i++) c.d[i + 1] += c.d[i] / 10, c.d[i] %= 10;c.clear();return c;}bool operator < (const bign& b){if (len != b.len) return len < b.len;for (int i = len - 1; i >= 0; i--)if (d[i] != b.d[i]) return d[i] < b.d[i];return false;}bool operator <= (const bign& b){if (len != b.len) return len < b.len;for (int i = len - 1; i >= 0; i--)if (d[i] != b.d[i]) return d[i] < b.d[i];return true;}bool operator > (const bign& b){if (len != b.len) return len > b.len;for (int i = len - 1; i >= 0; i--)if (d[i] != b.d[i]) return d[i] > b.d[i];return false;}bool operator >= (const bign& b){if (len != b.len) return len > b.len;for (int i = len - 1; i >= 0; i--)if (d[i] != b.d[i]) return d[i] > b.d[i];return true;}bign operator+=(const bign& b){*this = *this + b;return *this;}bign operator-=(const bign& b){*this = *this - b;return *this;}bign operator*=(const bign& b){*this = *this * b;return *this;}void print(){for (int i = len - 1; i >= 0; i--) std::cout << d[i];cout << '\n';}string str(){string res = "";for (int i = 0; i < len; i++) res = (char)(d[i] + '0') + res;return res;}
};
istream& operator >>(istream& in, bign& x)
{string s;in >> s;x = s.c_str();return in;
}
ostream& operator <<(ostream& out, bign& x)
{out << x.str();return out;
}
int main()
{bign a,b,c;cin>>a>>b;c=a+b;cout<<c<<'\n';
}