Segment Tree normal (2.0)

#include<bits/stdc++.h>
#define mx 100005
using namespace std;

int a[mx];
int tree[mx*4];

void build_tree(int node,int b,int e)
{
    tree[node]=0;
    if(b==e)
    {
        tree[node]=a[b];
        return;
    }
    int left=node*2;
    int right=node*2+1;
    int mid=(b+e)/2;
    build_tree(left, b ,mid);
    build_tree(right, mid+1, e);

    tree[node]=tree[left]+tree[right];           ///only changes will be made here

}

int query(int node, int b, int e, int i, int j)
{
    if(i>e || j<b) /// gone in the right or left
    {
        return 0;
    }
    if(b>=i && e<=j) return tree[node];

    int left=node*2;
    int right=node*2+1;
    int mid=(b+e)/2;
    int ret1=query(left, b ,mid,i,j);
    int ret2=query(right, mid+1, e,i,j);
   return ret1+ret2;                       ///only changes will be made here
}

void update(int node, int b, int e, int i, int new_val)
{
    // i is the position that is being updated

    if(i>e || i<b) /// gone in the right or left
    {
        return;
    }
    if(b>=i && e<=i)
    {
        if(new_val==-1)
        {
             printf("%d\n",tree[node]);
             tree[node]=0;
        }

       else
            tree[node]+=new_val;  //changes could be here as well
        return;
    }
    int left=node*2;
    int right=node*2+1;
    int mid=(b+e)/2;

    if(i<=mid)
    update(left, b ,mid,i,new_val);
    else
    update(right, mid+1, e,i,new_val);

    tree[node]= tree[left] + tree[right];           ///only changes will be made here
}

int main()
{
  // freopen("input.txt","r",stdin);  //input query indexing 0 theke hole query te
                                                                //x+1 , y+1 korte hobe

    int n,t,cs=1,q;
    int x,y;
    int input;

    cin>>t;
    while(t--)
    {

    cin>>n>>q;
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&a[i]);
    }


    build_tree(1,1,n);

    printf("Case %d:\n",cs++);
    while(q--)
    {
        scanf("%d",&input);
        if(input==1)
        {
            scanf("%d",&x);

            update(1,1,n,x+1,-1);
        }
        else  if(input==2)
        {
            scanf("%d%d",&x,&y);

            update(1,1,n,x+1,y);
        } else  if(input==3)
        {
             scanf("%d%d",&x,&y);
            int z=query(1,1,n,x+1,y+1);
            printf("%d\n",z);
        }

    }

    }



    return 0;
}