状态压缩

0; //空集
i<<i; //只含第i的元素的集合{i}
(1<<n)-1;//含有全部i个元素的集合{0,1,2,3,...,n-1}
if(S>>i & 1); //判断第i个元素是否属于集合sp
S|1<<i;//向集合S中加入第i个元素
S&~(1<<i);//从集合S中去除第i个元素
S|T;//集合S与集合T的并
S&T;//集合S与集合T的交

for(int i = 0 ; i < 1 << n ; i++) //枚举集合{0,1,2,3,...,n-1}的全部子集
{
  ;//对子集的处理
}

最长不升子序列(n \log n)

//m[0,1,2,3....,n-1] 输入的原始序列
//dp[i]表示长度为i的子序列的最后一个元素的最大值
memset(dp,0,sizeof(dp));
for(int i = 0; i < n ; i++)
  {
    *std::upper_bound(dp+1,dp+1+n,m[i],std::greater<int>()) = m[i];
  }
int ret = 1;
while(dp[ret] != 0)
  {
    ret++;
  }
  ret = ret -1;

最长递增子序列(n\log n)

//l[0,1,2,3....,n-1] 输入的原始序列
//dp[i]表示长度为i的子序列的最后一个元素可以允许的最小值
for(int i = 0 ; i <= idx ; i++)
  dp[i] = INT_MAX;
for(int i = 0 ; i < idx ; i++)
{
    *lower_bound(dp + 1, dp + idx, l[i]) = l[i];
}
int ret = 1;
while(dp[ret]!=INT_MAX)
  ret++;
ret = ret - 1;

最长递减子序列(n^2)

int ret = 1;
for(int i = 0 ; i < idx ; i++)
{
    for(int j = 1 ; j <= ret ; j++)
    {
        if(p[i].y >= dp[j])
        {
            dp[j] = p[i].y;
            break;
        }
    }
    if(dp[ret] != 0 ) ret = ret + 1;
}
ret = ret -1;

最长不增子序列(n^2)

int ret = 1;
for(int i = 0 ; i < m ; i++)
{
    for(int j = 1; j <= ret ; j++ )
    {
        if( dp[j] < dolls[i].h )
        {
            dp[j] = dolls[i].h;
            break;
        }
    }
    if(dp[ret] != 0 ) ret ++;
}
ret = ret -1;

数值方法

快速幂

// b不能是負數
int pow(int a, int b)   // aᵇ
{
    int x = 1;
    while(b>0)
    {
        if (b & 1)
            x =x * a;
        a = a * a;
        b = b / 2;
    }
    return x;
}

// b不能是負數
uint32_t pow_mod(uint32_t a,uint32_t b ,uint32_t m)   // aᵇ mod m
{
  int32_t x = 1;
  a = a % m;
  while(b>0)
    {
      if (b & 1)
        x =(x * a) % m;
      a = (a * a) %m;
      b = b / 2;
    }
  return x;
}

完全高精度

//HDU 1134 求卡特兰数
#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string.h>
using namespace std;
/*
* 完全大数模板
*输出cin>>a
*输出a.print();
* 注意这个输入不能自动去掉前导0的,可以先读入到char数组,去掉前导0,再用构造函数。
*/
#define MAXN 9999
#define MAXSIZE 1010
#define DLEN 4
using std::istream;
using std::ostream;
class BigNum
{
  private:
    int a[500]; //可以控制大数的位数
    int len;

  public:
    BigNum(){len = 1;memset(a, 0, sizeof(a));}       //构造函数
    BigNum(const int);                               //将一个int类型的变量转化成大数
    BigNum(const char *);                            //将一个字符串类型的变量转化为大数
    BigNum(const BigNum &);                          //拷贝构造函数
    BigNum &operator=(const BigNum &);               //重载赋值运算符,大数之间进行赋值运算
    friend istream &operator>>(istream &, BigNum &); //重载输入运算符
    friend ostream &operator<<(ostream &, BigNum &); //重载输出运算符

    BigNum operator+(const BigNum &) const;          //重载加法运算符,两个大数之间的相加运算
    BigNum operator-(const BigNum &) const;          //重载减法运算符,两个大数之间的相减运算
    BigNum operator*(const BigNum &)const;           //重载乘法运算符,两个大数之间的相乘运算
    BigNum operator/(const int &)const;              //重载除法运算符,大数对一个整数进行相除运算
    BigNum operator^(const int &) const;             //大数的n次方运算

    int operator%(const int &) const;                //大数对一个int类型的变量进行取模运算
    bool operator>(const BigNum &T) const;           //大数和另一个大数的大小比较
    bool operator>(const int &t) const;              //大数和一个int类型的变量的大小比较

    void print(); //输出大数
};

BigNum::BigNum(const int b) //将一个int类型的变量转化为大数
{
    int c, d = b;
    len = 0;
    memset(a, 0, sizeof(a));
    while (d > MAXN)
    {
        c = d - (d / (MAXN + 1)) * (MAXN + 1);
        d = d / (MAXN + 1);
        a[len++] = c;
    }
    a[len++] = d;
}
BigNum::BigNum(const char *s) //将一个字符串类型的变量转化为大数
{
    int t, k, index, L, i;
    memset(a, 0, sizeof(a));
    L = strlen(s);
    len = L / DLEN;
    if (L % DLEN)
        len++;
    index = 0;
    for (i = L - 1; i >= 0; i -= DLEN)
    {
        t = 0;
        k = i - DLEN + 1;
        if (k < 0)
            k = 0;
        for (int j = k; j <= i; j++)
            t = t * 10 + s[j] - '0';
        a[index++] = t;
    }
}
BigNum::BigNum(const BigNum &T) : len(T.len) //拷贝构造函数
{
    int i;
    memset(a, 0, sizeof(a));
    for (i = 0; i < len; i++)
        a[i] = T.a[i];
}
BigNum &BigNum::operator=(const BigNum &n) //重载赋值运算符,大数之间赋值运算
{
    int i;
    len = n.len;
    memset(a, 0, sizeof(a));
    for (i = 0; i < len; i++)
        a[i] = n.a[i];
    return *this;
}
istream &operator>>(istream &in, BigNum &b)
{
    char ch[MAXSIZE * 4];
    int i = -1;
    in >> ch;

    int L = strlen(ch);
    int count = 0, sum = 0;
    for (i = L - 1; i >= 0;)
    {
        sum = 0;
        int t = 1;
        for (int j = 0; j < 4 && i >= 0; j++, i--, t *= 10)
        {
            sum += (ch[i] - '0') * t;
        }
        b.a[count] = sum;
        count++;
    }
    b.len = count++;
    return in;
}
ostream &operator<<(ostream &out, BigNum &b) //重载输出运算符
{
    int i;
    cout << b.a[b.len - 1];
    for (i = b.len - 2; i >= 0; i--)
    {
        printf("%04d", b.a[i]);
    }
    return out;
}
BigNum BigNum::operator+(const BigNum &T) const //两个大数之间的相加运算
{
    BigNum t(*this);
    int i, big;
    big = T.len > len ? T.len : len;
    for (i = 0; i < big; i++)
    {
        t.a[i] += T.a[i];
        if (t.a[i] > MAXN)
        {
            t.a[i + 1]++;
            t.a[i] -= MAXN + 1;
        }
    }
    if (t.a[big] != 0)
        t.len = big + 1;
    else
        t.len = big;
    return t;
}
BigNum BigNum::operator-(const BigNum &T) const //两个大数之间的相减运算
{
    int i, j, big;
    bool flag;
    BigNum t1, t2;
    if (*this > T)
    {
        t1 = *this;
        t2 = T;
        flag = 0;
    }
    else
    {

        t1 = T;
        t2 = *this;
        flag = 1;
    }
    big = t1.len;
    for (i = 0; i < big; i++)
    {
        if (t1.a[i] < t2.a[i])
        {
            j = i + 1;
            while (t1.a[j] == 0)
                j++;
            t1.a[j--]--;
            while (j > i)
                t1.a[j--] += MAXN;
            t1.a[i] += MAXN + 1 - t2.a[i];
        }
        else
            t1.a[i] -= t2.a[i];
    }
    t1.len = big;
    while (t1.a[len - 1] == 0 && t1.len > 1)
    {
        t1.len--;
        big--;
    }
    if (flag)
        t1.a[big - 1] = 0 - t1.a[big - 1];
    return t1;
}
BigNum BigNum::operator*(const BigNum &T) const //两个大数之间的相乘
{
    BigNum ret;
    int i, j, up;
    int temp, temp1;
    for (i = 0; i < len; i++)
    {
        up = 0;
        for (j = 0; j < T.len; j++)
        {
            temp = a[i] * T.a[j] + ret.a[i + j] + up;
            if (temp > MAXN)
            {
                temp1 = temp - temp / (MAXN + 1) * (MAXN + 1);
                up = temp / (MAXN + 1);
                ret.a[i + j] = temp1;
            }
            else
            {
                up = 0;
                ret.a[i + j] = temp;
            }
        }
        if (up != 0)
            ret.a[i + j] = up;
    }
    ret.len = i + j;
    while (ret.a[ret.len - 1] == 0 && ret.len > 1)
        ret.len--;
    return ret;
}
BigNum BigNum::operator/(const int &b) const //大数对一个整数进行相除运算
{
    BigNum ret;
    int i, down = 0;
    for (i = len - 1; i >= 0; i--)
    {
        ret.a[i] = (a[i] + down * (MAXN + 1)) / b;
        down = a[i] + down * (MAXN + 1) - ret.a[i] * b;
    }
    ret.len = len;
    while (ret.a[ret.len - 1] == 0 && ret.len > 1)
        ret.len--;
    return ret;
}
int BigNum::operator%(const int &b) const //大数对一个 int类型的变量进行取模
{
    int i, d = 0;
    for (i = len - 1; i >= 0; i--)
        d = ((d * (MAXN + 1)) % b + a[i]) % b;
    return d;
}
BigNum BigNum::operator^(const int &n) const //大数的n次方运算
{
    BigNum t, ret(1);
    int i;
    if (n < 0)
        exit(-1);
    if (n == 0)
        return 1;
    if (n == 1)
        return *this;
    int m = n;
    while (m > 1)
    {
        t = *this;
        for (i = 1; (i << 1) <= m; i <<= 1)
            t = t * t;
        m -= i;
        ret = ret * t;
        if (m == 1)
            ret = ret * (*this);
    }
    return ret;
}
bool BigNum::operator>(const BigNum &T) const //大数和另一个大数的大小比较
{
    int ln;
    if (len > T.len)
        return true;
    else if (len == T.len)
    {
        ln = len - 1;
        while (a[ln] == T.a[ln] && ln >= 0)
            ln--;
        if (ln >= 0 && a[ln] > T.a[ln])
            return true;
        else
            return false;
    }
    else
        return false;
}

bool BigNum::operator>(const int &t) const //大数和一个int类型的变量的大小比较
{
    BigNum b(t);
    return *this > b;
}
void BigNum::print() //输出大数
{
    int i;
    printf("%d", a[len - 1]);
    for (i = len - 2; i >= 0; i--)
        printf("%04d", a[i]);
    printf("\n");
}
BigNum f[110]; //卡特兰数

int main()
{
    f[0] = 1;
    for (int i = 1; i <= 100; i++)
        f[i] = f[i - 1] * (4 * i - 2) / (i + 1); //卡特兰数递推式
    int n;
    while (scanf("%d", &n) == 1)
    {
        if (n == -1)
            break;
        f[n].print();
    }
    return 0;
}

数据结构

Trie树

struct Trie
{
    int ch[maxnod][sigma_size];
    int val[maxnod];// 附加信息
    int prefix[maxnod];//记录前缀数目
    int sz;//
    Trie(){sz = 1;memset(ch[0],0,sizeof(ch[0]));};
    int idx(char c) {return c - 'A';}
    
    //插入字符串s,附加信息v。
    int insert(char* s,int v)
    {
        int u = 0, n = strlen(s);
        for(int i = 0; i < n ; i++)
        {
            int c = idx(s[i]);
            if(!ch[u][c])
            {
                memset(ch[sz],0,sizeof(ch[sz]));
                val[sz] = 0;// 0表示中间结点
                prefix[sz] = 0;
                ch[u][c] = sz++;
            }
            u = ch[u][c];
            prefix[u]++;
        }
        val[u] = v;
    }

    int find(char* s)
    {
        int u = 0,n = strlen(s);
        for(int i = 0; i < n ; i++)
        {
            int c = idx(s[i]);
            if(!ch[u][c]) return 0 ;
            u = ch[u][c];
        }
        if(val[u]==0) return 0;
        else return 1;
    }
};