Added Segment Tree Library

c++/segment_tree.cpp

@@ -0,0 +1,116 @@
+#include<bits/stdc++.h>                                        //  ॐ           
+#include<ext/pb_ds/tree_policy.hpp>                            // Har Har Mahadev                                                    
+#include<ext/pb_ds/assoc_container.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <typename T>
+using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
+
+
+#define rep(i, zz, n) for (int i = zz; i < (n); ++i)
+#define all(x) x.begin(), x.end()
+#define pb push_back
+#define F first
+#define S second
+#define ll long long
+#define ld long double
+#define pll pair<ll, ll>
+#define PI 3.14159265358979323846
+#define el '\n'
+#define sp " "
+#define vl vector<ll>
+#define dbg(x) cout << #x << ": " << x << " ";
+
+const ll mod = 1e9 + 7;
+const ll inf = 1e18;
+const ll N = 1e6 + 5;
+
+#define     debug(x)    cout << #x << " "; _print(x); cout << '\n';
+#define     _debug(a,b) cout << #a << " [ "; array_debug(a,b); cout << "]\n";
+template <class T, class V> void array_debug(T *a, V n){ rep(i,0,n) cout << a[i] << ' ';}
+template <class T>          void _print(T t) {cout << t;}
+template <class T, class V> void _print(pair <T, V> p) {cout << "{"; _print(p.ff); cout << ","; _print(p.ss); cout << "}";}
+template <class T>          void _print(vector <T> v) {cout << "[ "; for (T i : v) {_print(i); cout << " ";} cout << "]";}
+template <class T>          void _print(set <T> v) {cout << "[ "; for (T i : v) {_print(i); cout << " ";} cout << "]";}
+template <class T>          void _print(multiset <T> v) {cout << "[ "; for (T i : v) {_print(i); cout << " ";} cout << "]";}
+template <class T, class V> void _print(map <T, V> v) {cout << "[ "; for (auto i : v) {_print(i); cout << " ";} cout << "]";}
+
+//greedy/brute force/DP/Graph/binary search/?
+
+template<typename T>
+struct SegmentTree{
+     vector<T> st;
+     void assign(vector<int> &v1) {
+          int n = (v1.size());
+          st = vector<T>(4 * n + 1);
+          build(v1, 1, 0, n - 1);
+     }
+     T combine(T x, T y) {
+          // T z;
+          // return z;
+          return { x.sum + y.sum }; // check which opeartion is to be performed
+     }
+     void build(vector<int>& v1, int v, int tl, int tr) {
+          if (tl == tr) {
+               st[v].sum = v1[tl]; //  check
+          }
+          else{
+               int mid = (tl + tr) / 2;
+               build(v1, 2 * v, tl, mid);
+               build(v1, 2 * v + 1, mid + 1, tr);
+               st[v] = combine(st[2 * v], st[2 * v + 1]);
+          }
+     }
+     // tl, tr   : the current segment/range whose node/vertex is v
+     //  l,  r   : the segment/range on which the 'range query' is to be performed
+     T query(int v, int tl, int tr, int l, int r) {
+          if (tr < l || r < tl) {
+               return { 0 }; // check which opeartion is to be performed
+          }
+          else if (tl == l && tr == r) {
+               return st[v];
+          }
+          int mid = (tl + tr) / 2;
+          return combine(query(2 * v, tl, mid, l, min(r, mid)), query(2 * v + 1, mid + 1, tr, max(l, mid + 1), r));
+     }
+     void update_one(int v, int tl, int tr, int pos, int newVal) {
+          if (tl == tr) {
+               st[v].sum = newVal;
+               // check whether the newVal is added or updated
+               return;
+          }
+          int mid = (tl + tr) / 2;
+          if (pos <= mid) {
+               update_one(2 * v, tl, mid, pos, newVal);
+          }
+          else{
+               update_one(2 * v + 1, mid + 1, tr, pos, newVal);
+          }
+          st[v] = combine(st[2 * v], st[2 * v + 1]);
+     }
+};
+struct Node{
+     int sum;
+};
+SegmentTree<Node> seg;
+
+
+void __roOTs(){          
+               // main code here
+
+}
+signed main(){
+    ios::sync_with_stdio(false);
+    cin.tie(0);
+    cout.tie(0);
+
+    int tt = 1; cin >> tt;
+    for (int i = 1; i <= tt; i++){
+        // cout << "Case #" << i << ": ";
+        __roOTs(); cout << '\n';
+
+    }
+    return 0;
+}