Merge pull request #533 from Abh-igyan/patch-5

Add data structure solution q1

Author: zonedoutdg

Problems/Data-structures/Day-09/sol/Abhigyan Tiwari/Solution1.cpp

@@ -0,0 +1,54 @@
+//submission: https://cses.fi/paste/dcc99ae97fc9eb1ef1b84d/
+
+// P.S.: Given salaries of n persons (from 1 to n) and queries in form of !,a,b or ?,a,b. If ! is there, then update salary of a person to a as b, if ? is there then find no.
+// of people having salary in range [a,b] and print it
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp> // Core PBDS header
+//We use a Policy based Data Structure, specifically: Tree (Red Black) with entries in ascending order so that all operations take logk time
+using namespace std;
+using namespace __gnu_pbds; // PBDS lives in this namespace
+
+using ll = long long;
+#define all(x) (x).begin(), (x).end()
+
+template<class T>
+using Tree=tree<T,null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
+const int inf=1e9+7;
+int sal[200005];
+
+
+void solve() {
+    int n,q;
+    cin>>n>>q;
+    Tree<pair<int,int>> ost;
+    for(int i=1;i<=n;i++){
+        cin>>sal[i];
+        ost.insert({sal[i],i});
+    }
+
+    while(q--){
+        char c; ll p,r;
+        cin>>c>>p>>r;
+        if(c=='!'){
+            ost.erase({sal[p],p});
+            ost.insert({r,p});
+            sal[p]=r;
+        }
+//order_of_key funtion gives elements count less than the element
+        else{
+            int count_upto_r=ost.order_of_key({r,inf});
+            int count_lessthan_p=ost.order_of_key({p,-1});
+            cout<<count_upto_r-count_lessthan_p<<endl;
+        }
+    }
+}
+// T.C.: O(Q*logn)
+//S.C: O(n)
+int main() {
+    // Fast I/O
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    solve();
+    return 0;
+}