Fenwick Tree

Author: Pankajcoder1

Fenwick_Tree.cpp

@@ -0,0 +1,159 @@
+/*
+    written by Pankaj Kumar.
+    country:-INDIA
+*/
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+using namespace std;
+using namespace __gnu_pbds;
+typedef long long ll ;
+typedef vector<ll> vl;
+#define speed cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);
+/*  Abbrevations  */
+#define ff first
+#define ss second
+#define mp make_pair
+#define line cout<<endl;
+#define pb push_back
+#define Endl "\n"
+// loops
+#define forin(arr,n) for(ll i=0;i<n;i++) cin>>arr[i];
+// Some print
+#define no cout<<"NO"<<endl;
+#define yes cout<<"YES"<<endl;
+// sort
+#define all(V) (V).begin(),(V).end()
+#define srt(V) sort(all(V))
+#define srtGreat(V) sort(all(V),greater<ll>())
+// some extra
+#define printv(v) for(ll i=0;i<ll(v.size());i++){cout<<v[i]<<" ";} line;
+#define sz(V) ll(V.size())
+// template
+template <typename T>
+T mymax(T x,T y)
+{
+    return (x>y)?x:y;
+}
+// function
+ll power(ll x,ll y,ll mod)
+{
+    ll res=1;
+    // x=x%mod;
+    while(y>0)
+    {
+        if(y%2==1)
+        {
+            res*=x;
+            // res=res%mod;
+        }
+        y/=2; x*=x; // x=x%mod;
+    }
+    return res;
+}
+ll str_to_num(string s)
+{
+    return stoi(s);
+}
+
+string num_to_str(ll num)
+{
+    return to_string(num);
+}
+// datatype definination
+#define ordered_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
+class Point
+{
+    public:
+        ll x;
+        ll y;
+        ll z;
+        ll getsum()
+        {
+            return x+y+z;
+        }
+};
+/* ascii value 
+A=65,Z=90,a=97,z=122
+*/
+/*  -----------------------------------------------------------------------------------*/
+// to run ctrl+b
+ll getsum(vector<ll> v,vector<ll>& FenwickTree,ll index)
+{
+    ll sum=0;
+    while(index>0)
+    {
+        cout<<"index is "<<index<<endl;
+        sum+=FenwickTree[index];
+        index-=(index&(-index));
+    }
+    return sum;
+}
+
+void update(vector<ll>& FenwickTree,ll index,ll n,ll value)
+{
+    while(index<=n)
+    {
+        FenwickTree[index]+=value;
+        index+=(index&(-index));
+    }
+}
+ll solve()
+{
+    cout<<"\tuse zero based indexing for query"<<endl;
+    cout<<"size of array "<<endl;
+    ll n,q,l,a,b;
+    cin>>n;
+    vector<ll> v(n,0);
+    vector<ll> FenwickTree(n+1,0);
+    cout<<"Enter element of array "<<endl;
+    for(ll i=0;i<n;i++)
+    {
+        cin>>v[i];
+        update(FenwickTree,i+1,n,v[i]);
+    }
+    cout<<"No of query "<<endl;
+    cin>>q;
+    while(q--)
+    {
+        cout<<"1.For update and 2. for sum"<<endl;
+        cin>>l;
+        if(l==1)
+        {
+            cout<<"Enter position and value "<<endl;
+            ll pos=0,value;
+            cin>>pos>>value;
+            pos++;
+            update(FenwickTree,pos,n,value);
+        }
+        else
+        {
+            cout<<"Sum upto:"<<endl;
+            cin>>a;
+            a++;
+            ll sum=getsum(v,FenwickTree,a);
+            cout<<"Required sum is "<<sum<<endl;
+        }
+    }
+    return 0;
+}
+
+int main()
+{
+    speed;
+    /* #ifndef ONLINE_JUDGE
+        freopen("input.txt","r",stdin);
+        freopen("output.txt","w",stdout);
+    #endif */
+    ll TestCase=1;
+    // cin>>TestCase;
+    while(TestCase--)
+    {
+        solve();
+    }
+}
+/* stuff you should look before submission 
+* int overflow
+* special test case (n=0||n=1||n=2)
+* don't get stuck on one approach if you get wrong answer
+*/