线段树

#include<stdio.h>
#include<string.h>
long long int tree[444444],lazy[444444];
void pushdown(int p,int l,int r)
{
if(lazy[p])
{
int mid=(l+r)/2;
lazy[2*p]+=lazy[p];
lazy[2*p+1]+=lazy[p];
tree[2*p]+=lazy[p]*(mid-l+1);
tree[2*p+1]+=lazy[p]*(r-mid);
lazy[p]=0;
}
}
void build(int p,int l,int r)
{
if(l==r)
{
scanf("%I64d",&tree[p]);
return;
}
int mid=(l+r)/2;
build(2*p,l,mid);
build(2*p+1,mid+1,r);
tree[p]=tree[2*p]+tree[2*p+1];
}
long long int find(int p,int l,int r,int x,int y)
{
if(x<=l&&y>=r)
return tree[p];
pushdown(p,l,r);
int mid=(l+r)/2;
long long int sum=0;
if(x<=mid) sum+=find(2*p,l,mid,x,y);
if(y>mid) sum+=find(2*p+1,mid+1,r,x,y);
return sum;
}
void change(int p,int l,int r,int x,int y,int sum)
{
if(x<=l&&y>=r)
{
lazy[p]+=sum;
tree[p]+=(long long)sum*(r-l+1);
return;
}
pushdown(p,l,r);
int mid=(l+r)/2;
if(x<=mid) change(2*p,l,mid,x,y,sum);
if(y>mid) change(2*p+1,mid+1,r,x,y,sum);
tree[p]=tree[2*p]+tree[2*p+1];
}
int main()
{
int m,n,x,y,sum;
char s[2];
memset(lazy,0,sizeof(lazy));
memset(tree,0,sizeof(tree));
scanf("%d%d",&n,&m);
build(1,1,n);
while(m--)
{
scanf("%s",s);
if(s[0]=='Q')
{
scanf("%d%d",&x,&y);
printf("%I64d\n",find(1,1,n,x,y));
}
else
{
scanf("%d%d%d",&x,&y,&sum);
change(1,1,n,x,y,sum);
}
}
}