Added code for Segment Tree

C++/Data Structure/max_num_in_range_SegmentTree.cpp

@@ -0,0 +1,178 @@
+#pragma GCC optimize("Ofast")
+#pragma GCC optimization("unroll-loops")
+#include <bits/stdc++.h>
+using namespace std;
+//#include <ext/pb_ds/assoc_container.hpp>
+//#include <ext/pb_ds/tree_policy.hpp>
+//using namespace __gnu_pbds;
+#define max(a, b) (a < b ? b : a)
+#define min(a, b) ((a > b) ? b : a)
+#define mod 1000000007
+#define set_bits __builtin_popcountll
+#define FOR(a, c) for (int(a) = 0; (a) < (c); (a)++)
+#define FORL(a, b, c) for (int(a) = (b); (a) <= (c); (a)++)
+#define FORR(a, b, c) for (int(a) = (b); (a) >= (c); (a)--)
+#define INF 1e18
+typedef long long int ll;
+typedef unsigned long long ull;
+typedef long double lld;
+//typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key
+typedef priority_queue<ll, vector<ll>, greater<ll>>  minhp;
+typedef priority_queue<ll> maxhp;
+typedef vector<ll> vi;
+typedef pair<int, int> pi;
+typedef vector<vector<ll>> vdp;
+typedef priority_queue <pi , vector<pi> , greater<pi>> minhppi;
+#define sz(x) (int)(x).size()
+#define F first
+#define S second
+#define PB push_back
+#define POB pop_back
+#define MP make_pair
+#define YES cout<<"YES"<<endl
+#define NO cout<<"NO"<<endl
+#define line cout<<endl
+#define all(x) (x).begin(), (x).end()
+
+#ifndef ONLINE_JUDGE
+#define dbg(x) cerr<<#x<<' ';_print(x);cerr<<endl;
+#else
+#define dbg(x)
+#endif
+
+void _print(int a) {cerr << a << ' ';}
+void _print(string a) {cerr << a << ' ';}
+void _print(char a) {cerr << a << ' ';}
+void _print(ll a) {cerr << a << ' ';}
+void _print(float a) {cerr << a << ' ';}
+void _print(ull a) {cerr << a << ' ';}
+void _print(lld a) {cerr << a << ' ';}
+void _print(double a) {cerr << a << ' ';}
+void _print(const char *x) {cerr << '"' << x << '"';}
+void _print(bool x) {cerr << (x ? "true" : "false");}
+void _print(const string &x) {cerr << '"' << x << '"';}
+
+template <class T, class V> void _print(pair <T, V> p);
+template <class T> void _print(vector <T> v);
+template <class T> void _print(set <T> v);
+template<class T> class Array;
+template <class T, class V> void _print(map <T, V> v);
+template <class T, class V> void _print(unordered_map <T, V> v);
+template <class T> void _print(multiset <T> v);
+template <class T> void _print(unordered_set <T> v);
+template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.F); cerr << ","; _print(p.S); cerr << "}";}
+template<class T> void _print(vector<T> v){cerr<<"[ ";for(T i: v){_print(i);cerr<<", ";}cerr<<"]"<<endl;}
+template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <class T, class V> void _print(unordered_map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
+template <typename T>void print(vector<vector<T> >& a){cerr << "[ ";for (auto i : a){print(i);cerr << " ";}cerr << "]";}
+template <typename T, typename V>void print(vector<pair<T, V> >& a){cerr << '[' << ' ';for (auto x : a){print(x.F);cerr << ":";print(x.S);cerr << ' ';}cerr << ']';}
+template <class T> void _print(unordered_set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
+
+
+const int N = 1e5+2;
+int a[N], tree[4*N];
+
+// partial querry and complete querry
+/*  Node 
+       1           // node 1 
+     2   3         // For left node*2 and right 2*node + 1
+    4 5  6 7       // For left node*2 i.e (2*4)&(3*2) and right 2*node + 1 i.e (2*4+1)&(3*2+1)
+
+*/
+// Construct Segment Tree using Build Function
+void build(int node, int st, int en){
+    // Agr st en same hai matlab leaf node par ho tum
+    if(st == en){
+        tree[node] = a[st];
+        return;
+    }
+    // Ab mid me dnc karo 
+    int m = (st+en)/2;
+    // Left me build karo
+    build(node*2, st, m);
+    // Right me build karo
+    build(node*2+1, m+1, en);
+
+    // Question prefix sum type ka hai isliye sum store ho raha hai isme
+    // Ye sum ka tree hai, sum in a given querry 
+    tree[node] = tree[node*2] + tree[node*2+1] ; 
+}
+
+// Fir this quuestion we are using solve func to construct our tree
+void solve(int node, int st, int en){
+    if(st==en){
+        tree[node] = a[st];// a[en] && a[st] dono same hai 
+        return; 
+    }
+    int m = (st+en)/2; 
+    solve(2*node, st, m);
+    solve(2*node+1, m+1, en);
+    tree[node] = max(tree[2*node] , tree[2*node+1]);
+}
+
+// st and en pe khelenge isme 
+int querry(int node, int st, int en, int l, int r){
+    // No overlap case
+    if(st>r || en<l) return INT_MIN; 
+    // Complete overlap case
+    if(st>=l && en<=r) return tree[node];
+    // Ab partial overlap case wale me we go down and chose own desired range
+    int m = (st+en)/2;
+    return max(querry(2*node, st, m, l, r) , querry(2*node+1, m+1, en, l, r));
+}
+
+// this will update that number and seg tree me bhi changes hoge isse
+void update(int node , int st, int en, int idx ,int val){
+    // index waise bhi leaf node me hi milega bro 
+    if(st==en){
+        a[st] = val;
+        tree[node] = val;
+        return;
+    }
+    int m = (st+en)/2;
+    // Binary search lag raha hai to find the ind of the number
+    if(idx<=m) update(2*node, st, m, idx, val);
+    else update(2*node+1, m+1, en, idx, val);
+    tree[node] = max(tree[2*node] , tree[2*node+1]);
+}
+
+int main(){
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+#ifndef ONLINE_JUDGE
+freopen("Error.txt", "w", stderr);
+#endif
+
+int n ; cin>>n ; 
+FOR(i, n){
+    cin>>a[i];
+}
+
+// Construct our Segment Tree structure 
+solve(1, 0, n-1);
+
+while(1){
+    int q; cin>>q;
+    // Exit the querries
+    if(q==-1) break;
+
+    // Find max in the given range 
+    if(q==1){
+        int l, r; cin>>l>>r;
+        cout<<querry(1, 0, n-1, l, r)<<endl;
+    }
+
+    // Update 
+    if(q==2){
+        int ind, val; cin>>ind>>val;
+        update(1,0,n-1,ind,val);
+        // Poore ka max nikal ke dikhao sahi hai ya nahi 
+        cout<<querry(1, 0, n-1, 0, n-1)<<endl;
+    }
+
+
+}
+return 0;}