Create Fenwick-Tree-Range-Sum.cpp

Fenwick-Tree-Range-Sum.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+void update(int BIT[], int x, int val, int n) {
+ for(; x<=n; x+=x&(-x)){
+ BIT[x]+=val;
+ }
+}
+
+int query(int BIT[], int x) {
+ int sum=0;
+ for(; x>0; x-=x&(-x)) {
+ sum+=BIT[x];
+ }
+ return sum;
+}
+
+int main() {
+ int N, Q, range;
+
+ cin >> N;
+ int arr[N+1];
+ int *BIT = (int*)calloc(N+1,sizeof(int));;
+
+ for(int i=1; i<N+1; ++i) {
+ cin >> arr[i];
+ update(BIT, i, arr[i], N);
+ }
+ cin >> Q; // number of query
+
+ while(Q--) {
+ cin >> range;
+ cout << query(BIT,range) << endl;
+ }
+ return 0;
+}