CodeForces Gym 100735I 模拟题（可套大数版）

#include<string>
#include<iostream>
#include<iosfwd>
#include<cmath>
#include<cstring>
#include<stdlib.h>
#include<stdio.h>
#include<cstring>
#define MAX_L 2005 //最大长度，可以修改
using namespace std;

class bign
{
public:
int len, s[MAX_L];//数的长度，记录数组
//构造函数
bign();
bign(const char*);
bign(int);
bool sign;//符号 1正数 0负数
string toStr() const;//转化为字符串，主要是便于输出
friend istream& operator>>(istream &, bign &);//重载输入流
friend ostream& operator<<(ostream &, bign &);//重载输出流
//重载复制
bign operator=(const char*);
bign operator=(int);
bign operator=(const string);
//重载各种比较
bool operator>(const bign &) const;
bool operator>=(const bign &) const;
bool operator<(const bign &) const;
bool operator<=(const bign &) const;
bool operator==(const bign &) const;
bool operator!=(const bign &) const;
//重载四则运算
bign operator+(const bign &) const;
bign operator++();
bign operator++(int);
bign operator+=(const bign&);
bign operator-(const bign &) const;
bign operator--();
bign operator--(int);
bign operator-=(const bign&);
bign operator*(const bign &)const;
bign operator*(const int num)const;
bign operator*=(const bign&);
bign operator/(const bign&)const;
bign operator/=(const bign&);
//四则运算的衍生运算
bign operator%(const bign&)const;//取模（余数）
bign factorial()const;//阶乘
bign Sqrt()const;//整数开根（向下取整）
bign pow(const bign&)const;//次方
//一些乱乱的函数
void clean();
~bign();
};
#define max(a,b) a>b ? a : b
#define min(a,b) a<b ? a : b

bign::bign()
{
memset(s, 0, sizeof(s));
len = 1;
sign = 1;
}

bign::bign(const char *num)
{
*this = num;
}

bign::bign(int num)
{
*this = num;
}

string bign::toStr() const
{
string res;
res = "";
for (int i = 0; i < len; i++)
res = (char)(s[i] + '0') + res;
if (res == "")
res = "0";
if (!sign&&res != "0")
res = "-" + res;
return res;
}

istream &operator>>(istream &in, bign &num)
{
string str;
in >> str;
num = str;
return in;
}

ostream &operator<<(ostream &out, bign &num)
{
out << num.toStr();
return out;
}

bign bign::operator=(const char *num)
{
memset(s, 0, sizeof(s));
char a[MAX_L] = "";
if (num[0] != '-')
strcpy(a, num);
else
for (int i = 1; i < strlen(num); i++)
a[i - 1] = num[i];
sign = !(num[0] == '-');
len = strlen(a);
for (int i = 0; i < strlen(a); i++)
s[i] = a[len - i - 1] - 48;
return *this;
}

bign bign::operator=(int num)
{
char temp[MAX_L];
sprintf(temp, "%d", num);
*this = temp;
return *this;
}

bign bign::operator=(const string num)
{
const char *tmp;
tmp = num.c_str();
*this = tmp;
return *this;
}

bool bign::operator<(const bign &num) const
{
if (sign^num.sign)
return num.sign;
if (len != num.len)
return len < num.len;
for (int i = len - 1; i >= 0; i--)
if (s[i] != num.s[i])
return sign ? (s[i] < num.s[i]) : (!(s[i] < num.s[i]));
return !sign;
}

bool bign::operator>(const bign&num)const
{
return num < *this;
}

bool bign::operator<=(const bign&num)const
{
return !(*this>num);
}

bool bign::operator>=(const bign&num)const
{
return !(*this<num);
}

bool bign::operator!=(const bign&num)const
{
return *this > num || *this < num;
}

bool bign::operator==(const bign&num)const
{
return !(num != *this);
}

bign bign::operator+(const bign &num) const
{
if (sign^num.sign)
{
bign tmp = sign ? num : *this;
tmp.sign = 1;
return sign ? *this - tmp : num - tmp;
}
bign result;
result.len = 0;
int temp = 0;
for (int i = 0; temp || i < (max(len, num.len)); i++)
{
int t = s[i] + num.s[i] + temp;
result.s[result.len++] = t % 10;
temp = t / 10;
}
result.sign = sign;
return result;
}

bign bign::operator++()
{
*this = *this + 1;
return *this;
}

bign bign::operator++(int)
{
bign old = *this;
++(*this);
return old;
}

bign bign::operator+=(const bign &num)
{
*this = *this + num;
return *this;
}

bign bign::operator-(const bign &num) const
{
bign b = num, a = *this;
if (!num.sign && !sign)
{
b.sign = 1;
a.sign = 1;
return b - a;
}
if (!b.sign)
{
b.sign = 1;
return a + b;
}
if (!a.sign)
{
a.sign = 1;
b = bign(0) - (a + b);
return b;
}
if (a<b)
{
bign c = (b - a);
c.sign = false;
return c;
}
bign result;
result.len = 0;
for (int i = 0, g = 0; i < a.len; i++)
{
int x = a.s[i] - g;
if (i < b.len) x -= b.s[i];
if (x >= 0) g = 0;
else
{
g = 1;
x += 10;
}
result.s[result.len++] = x;
}
result.clean();
return result;
}

bign bign::operator * (const bign &num)const
{
bign result;
result.len = len + num.len;

for (int i = 0; i < len; i++)
for (int j = 0; j < num.len; j++)
result.s[i + j] += s[i] * num.s[j];

for (int i = 0; i < result.len; i++)
{
result.s[i + 1] += result.s[i] / 10;
result.s[i] %= 10;
}
result.clean();
result.sign = !(sign^num.sign);
return result;
}

bign bign::operator*(const int num)const
{
bign x = num;
bign z = *this;
return x*z;
}
bign bign::operator*=(const bign&num)
{
*this = *this * num;
return *this;
}

bign bign::operator /(const bign&num)const
{
bign ans;
ans.len = len - num.len + 1;
if (ans.len < 0)
{
ans.len = 1;
return ans;
}

bign divisor = *this, divid = num;
divisor.sign = divid.sign = 1;
int k = ans.len - 1;
int j = len - 1;
while (k >= 0)
{
while (divisor.s[j] == 0) j--;
if (k > j) k = j;
char z[MAX_L];
memset(z, 0, sizeof(z));
for (int i = j; i >= k; i--)
z[j - i] = divisor.s[i] + '0';
bign dividend = z;
if (dividend < divid) { k--; continue; }
int key = 0;
while (divid*key <= dividend) key++;
key--;
ans.s[k] = key;
bign temp = divid*key;
for (int i = 0; i < k; i++)
temp = temp * 10;
divisor = divisor - temp;
k--;
}
ans.clean();
ans.sign = !(sign^num.sign);
return ans;
}

bign bign::operator/=(const bign&num)
{
*this = *this / num;
return *this;
}

bign bign::operator%(const bign& num)const
{
bign a = *this, b = num;
a.sign = b.sign = 1;
bign result, temp = a / b*b;
result = a - temp;
result.sign = sign;
return result;
}

bign bign::pow(const bign& num)const
{
bign result = 1;
for (bign i = 0; i < num; i++)
result = result*(*this);
return result;
}

bign bign::factorial()const
{
bign result = 1;
for (bign i = 1; i <= *this; i++)
result *= i;
return result;
}

void bign::clean()
{
if (len == 0) len++;
while (len > 1 && s[len - 1] == '\0')
len--;
}

bign bign::Sqrt()const
{
if (*this<0)return -1;
if (*this <= 1)return *this;
bign l = 0, r = *this, mid;
while (r - l>1)
{
mid = (l + r) / 2;
if (mid*mid>*this)
r = mid;
else
l = mid;
}
return l;
}

bign::~bign()
{
}
bign num[3];
bool work()
{
for (int i = 0; i < 3; ++i)
{
for (int j = 0; j < 3; ++j)
{
for (int k = 0; k < 3; ++k)
{
if (num[i] + num[j] == num[k])
return true;
}
}
}
return false;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
for (int i = 0; i < 3; ++i)
cin >> num[i];
bool flag = work();
if (flag)
cout << "YES" << endl;
else
cout << "NO" << endl;
//while (1);
return 0;
}