Data structure--segment Tree II (c + +)

Source:

#include <cstdio>
int n,num (0), h[100001];
struct Treetype
{
int left,right,lefts,rights,sum,sign;
}i[200020];
void x1 (int t1,int T2)//achievements.
{
int t=++num;
i[t].left=t1;
i[t].right=t2;
if (t1!=t2-1)
{
i[t].lefts=num+1;
X1 (T1, (T1+T2)/2);
i[t].rights=num+1;
X1 ((T1+T2)/2,t2);
i[t].sum=i[i[t].lefts].sum+i[i[t].rights].sum;
}
Else
I[T].SUM=H[T1];
}
void lazy (int t)//Use Jingxiang's lazy algorithm to deepen one layer down.
{
i[i[t].lefts].sum+=i[t].sign* (i[i[t].lefts].right-i[i[t].lefts].left);
i[i[t].rights].sum+=i[t].sign* (i[i[t].rights].right-i[i[t].rights].left);
i[i[t].lefts].sign+=i[t].sign;
i[i[t].rights].sign+=i[t].sign;
i[t].sign=0;
}
void x2 (int t,int x,int y,int z)
{
if (x<=i[t].left&&y>=i[t].right)
{
i[t].sum+=z* (i[t].right-i[t].left);
i[t].sign+=z;//may also have a processed mark, so it should be superimposed.
}
Else
{
if (i[t].sign)//To continue searching down, prepare ahead.
lazy (t);
if (x< (i[t].left+i[t].right)/2)
x2 (i[t].lefts,x,y,z);
if (y> (i[t].left+i[t].right)/2)
x2 (i[t].rights,x,y,z);
i[t].sum=i[i[t].lefts].sum+i[i[t].rights].sum;
}
}
int x3 (int t,int x,int y)//sum.
{
if (x<=i[t].left&&y>=i[t].right)
return i[t].sum;
if (i[t].sign)//the same as above, to continue searching down, prepare ahead.
lazy (t);
int ans (0);
if (x< (i[t].left+i[t].right)/2)
ans+=x3 (i[t].lefts,x,y);
if (y> (i[t].left+i[t].right)/2)
ans+=x3 (i[t].rights,x,y);
return ans;
}
int main ()
{
scanf ("%d", &n);
for (int a=1;a<=n;a++)
scanf ("%d", &h[a]);
X1 (1,n+1);
scanf ("%d", &n);
for (int a=1;a<=n;a++)
{
int t;
scanf ("%d", &t);
if (t==1)
{
int x, y, Z;
scanf ("%d%d%d", &x,&y,&z);//Modify the interval range.
x2 (1,x,y+1,z);//semi-closed half-open interval processing.
}
Else
{
int x, y;
scanf ("%d%d", &x,&y);
printf ("%d\n", X3 (1,x,y+1));//The same as above, the semi-closed half-open interval in the form of processing.
}
}
return 0;
}

Data structure--segment Tree II (c + +)