LabASD 3.B

#include <iostream>
#include <cmath>
#include <queue>

using namespace std;

struct node{
    node* from=NULL;
    node* left=NULL;
    node* right=NULL;
    int value;
    node(node *from){
        this->from=from;
    }
    node();
};


node* head=new node();

int D=0;
vector<int> base;
vector<node*> base_nods;

int build_tree(node *curent,int deep,int cur){
    node* left=new node(curent);
    node* right=new node(curent);
    int L,R;
    if(cur!=deep){
        curent->left=left;
        curent->right=right;
        L=build_tree(left,deep,cur+1);
        R=build_tree(right,deep,cur+1);
        curent->value=R+L;
        return R+L;}
    else {
        base_nods.push_back(curent);
        if(D<base.size()){
            curent->value = base[D];
        D++;}
        else
            curent->value = 0;
        return curent->value;
    }
}

int left_summ(node* cur){
    if(cur->from!=NULL){
        if(cur->from->left!=cur)
            return (cur->from->left->value)+left_summ(cur->from);
        else
            return left_summ(cur->from);}
    else
        return 0;
}

int right_summ(node* cur){
    if(cur->from!=NULL){
        if(cur->from->right!=cur)
            return (cur->from->right->value)+left_summ(cur->from);
        else
            return left_summ(cur->from);}
    else
        return 0;
}


int main() {
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        int tmp;
        cin>>tmp;
        base.push_back(tmp);
    }
    int deep=log2(n);
    if(n!=pow(2,deep))
        deep++;
    build_tree(head,deep,0);
    string command;
    int a,b;
    while(cin>>command){
        if(command=="set"){
            cin>>a>>b;
            base_nods[a-1]->value=b;
        }
        else{
            cin>>a>>b;
            a=left_summ(base_nods[a-1]);
            b=right_summ(base_nods[b-1]);
        }
    }
    return 0;
}