#include
#include
using namespace std;
#define MAXSIZE 1000
void build_tree(int arr[], int tree[], int node, int start, int end){
if(start == end){
tree[node] = arr[start];
}else{
int mid = (start + end) / 2;
int left = 2 * node + 1;
int right = 2 * node + 2;
build_tree(arr, tree, left,start,mid );
build_tree(arr, tree, right, mid + 1, end);
tree[node] = tree[left] + tree[right];
}
}
void update_tree(int arr[], int tree[], int node, int start, int end, int ind, int val){
if(start == end){
arr[ind] = val;
tree[node] = val;
return;
}
int mid = (start + end) / 2;
int left = 2 * node + 1;
int right = 2 * node + 2;
if(ind >= start && ind <= mid){
update_tree(arr, tree, left, start, mid, ind, val);
}
else{
update_tree(arr, tree, right, mid + 1, end, ind, val);
}
tree[node] = tree[left] + tree[right];
}
int qurry_tree(int arr[], int tree[], int node, int start, int end, int l, int r){
cout << "start: " << start << " end: "<< end << endl;
if(l > end || r < start) return 0;
if(l<=start && r >=end){
return tree[node];
}
if(start == end){
return tree[node];
}
int mid = (start + end) / 2;
int left = 2 * node + 1;
int right = 2 * node + 2;
int sum_left = qurry_tree(arr, tree, left, start, mid, l, r);
int sum_right = qurry_tree(arr, tree, right, mid + 1, end, l, r);
return sum_left + sum_right;
}
int main(){
int arr[] = {1,3,5,7,9,11};
int size = 6;
int tree[MAXSIZE] = {0};
build_tree(arr,tree, 0, 0, size - 1);
cout << endl;
update_tree(arr, tree, 0, 0,size - 1, 4,6);
int ans = qurry_tree(arr, tree, 0, 0, size -1, 2, 5);
cout << "ans = " << ans << endl;
return 0;
}