added fenwick tree

Author: offamitkumar

Data-Structures/Fenwick-Tree/fenwick.cpp

@@ -0,0 +1,116 @@
+//  Author : Amit Kumar 
+
+//  #include <ext/pb_ds/assoc_container.hpp>
+//  #include <ext/pb_ds/tree_policy.hpp>
+
+#include <iostream>
+#include <algorithm> 
+#include <string> 
+//  #include <sstream> 
+//  #include <fstream>
+//  #include <iomanip> 
+#include <chrono> 
+#include <numeric>
+#include <utility>
+#include <functional>
+
+#include <bitset>
+#include <tuple>
+#include <queue>
+#include <stack>
+#include <vector>
+#include <array>
+//  #include <unordered_map>
+//  #include <unordered_set>
+#include <set>
+#include <map>
+//  #include <deque>
+
+#include <climits>
+#include <cstring>
+#include <cmath>
+#include <cassert>
+#include <cstdio>
+using namespace std;
+using namespace std::chrono;
+//  using namespace placeholders;
+//  using namespace __gnu_pbds;
+//  template<typename TypeInfo>
+//  using new_set = tree< // find_by_order & order_of_key
+//                   TypeInfo ,
+//                   null_type ,
+//                   less<TypeInfo> ,
+//                   rb_tree_tag ,
+//                   tree_order_statistics_node_update 
+//       > ;
+
+void debug_out() { cerr << endl; }
+ 
+template <typename HEAD, typename... TAIL>
+void debug_out(HEAD H, TAIL... T) {
+  cerr << " " << to_string(H);
+  debug_out(T...);
+}
+ 
+#ifdef HELL_JUDGE
+#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
+#else
+#define debug(...) 0
+#endif
+ 
+
+const long long MAXM = (long long)1e5+100;
+const long long MAXN = 5000100;
+const long long MOD = (long long)1e9+7;
+
+vector<long long>ftree(MAXN);
+#define MSB(X) ((X)&(-X))
+
+void update(long long a, long long val){
+    a+=1;
+    while(a<MAXN){
+        ftree[a]+=val;
+        a+=MSB(a);
+    }
+    return;
+}
+
+long long query(long long a){
+    long long sum=ftree[0];
+    while(a>0){
+        sum+=ftree[a];
+        a-=MSB(a);
+    }
+    return sum;
+}
+
+int main(void){
+#ifdef HELL_JUDGE
+    freopen("input","r",stdin);
+    freopen("output","w",stdout);
+    freopen("error","w",stderr);
+#endif 
+#ifdef HELL_JUDGE
+    auto INITIAL_TIME = high_resolution_clock::now();
+#endif 
+    ios::sync_with_stdio(false);
+    cin.tie(0);
+    long long n,m; cin >> n >> m; 
+    while(m--){
+        char c; cin >> c; 
+        if(c=='+'){
+            long long a,b; cin >> a >> b;
+            update(a , b);
+        }else{
+            long long a; cin >> a;
+            cout << query(a) << '\n'; 
+        }
+    }
+#ifdef HELL_JUDGE
+    auto FINAL_TIME = high_resolution_clock::now();
+    cout << "Time : "
+        << duration_cast<milliseconds>(FINAL_TIME-INITIAL_TIME).count() 
+        << " ms" << '\n'; 
+#endif 
+    return 0;
+}