树状数组的三种操作

直接贴代码

一、改点求段
namespace BIT
{
#define N 100000
#define lowbit(a) ((a)&(-a))
int c[N],num;
void init(int n){num=n;}
inline void add(int x,int a)
{
int xx=x;
while(xx<=num)c[xx]+=a,xx+=lowbit(xx);
}
inline int sum(int x)
{
int sum_=0,xx=x;
while(xx)sum_+=c[xx],xx-=lowbit(xx);
return sum_;
}
inline int sum(int l,int r)
{
return sum(r)-sum(l-1);
}
#undef N
#undef lowbit
};

二、改段求点
namespace BIT
{
#define N 100000
#define lowbit(a) ((a)&(-a))
int c[N],b[N],num;
void init(int n){num=n;}
inline void add(int l,int r,int x)
{
for(int i=l-1;i;i-=lowbit(i))b[i]-=x;
for(int i=r;i;i-=lowbit(i))b[i]+=x;
}
inline int sum(int x)
{
int s=0;
for(int i=x;i<=num;i+=lowbit(i))s+=b[i];
return s;
}
#undef N
#undef lowbit
};

三、改段求段`

namespace BIT
{
#define lowbit(x) ((x)&(-x))
#define cl(x) memset(x,0,sizeof(x))
int b[100010],c[100010],maxn;
void init(int n){maxn=n;cl(b);cl(c);}
inline void add(int l,int r,int x)
{
for(int i=r;i;i-=lowbit(i))b[i]+=x;
for(int i=r;i<=maxn;i+=lowbit(i))c[i]+=x*r;
if(l>1)
{
for(int i=l-1;i;i-=lowbit(i))b[i]-=x;
for(int i=l-1;i<=maxn;i+=lowbit(i))c[i]-=x*(l-1);
}
}
inline int sum(int x)
{
int s=0;
if(x>1)
{
for(int i=x;i<=maxn;i+=lowbit(i))s+=b[i];
s*=x;
for(int i=x-1;i;i-=lowbit(i))s+=c[i];
}
return s;
}
inline int sum(int l,int r)
{
return sum(r)-sum(l-1);
}
#undef lowbit
#undef cl
};`