Update and rename segmentTree.cpp to segmentTreeForSum.cpp

C++/segmentTreeForSum.cpp

@@ -0,0 +1,132 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
+#define MOD 1000000007
+#define MOD1 998244353
+#define INF 1e18
+#define endl "\n"
+#define pb push_back
+#define ppb pop_back
+#define mp make_pair
+#define ff first
+#define ss second
+#define PI 3.141592653589793238462
+#define set_bits __builtin_popcountll
+#define sz(x) ((int)(x).size())
+#define all(x) (x).begin(), (x).end()
+#define mem(a, b) memset(a, b, sizeof(a))
+#define int long long int
+
+
+typedef long long ll;
+typedef unsigned long long ull;
+typedef long double lld;
+
+// segmentTree
+
+class segmentTree{
+public:
+    vector<int> tree; 
+    int identity = 0; 
+    int N; 
+
+    int merge(int a, int b){
+        return a + b;
+    }
+    segmentTree(int size, int identity){
+        N = size; 
+        this->identity = identity;  
+        tree.assign(4 * N, identity);       
+    }   
+
+
+    // update query 
+
+    void update(int qIdx, int val){
+
+
+        // lambda function 
+        function<void(int, int, int)> f = [&](int tIdx, int tL, int tR){
+
+            // base case
+            if(tL == tR){
+                tree[tIdx] = val; 
+                return;
+            }
+
+            int tM = tL + (tR - tL) / 2; 
+
+            // conditions
+
+            if(tL <= qIdx && qIdx <= tM){
+                // go left
+                f(2 * tIdx + 1, tL, tM);
+            }
+            else{
+                // go right
+                f(2 * tIdx + 2, tM + 1, tR);
+            }
+
+            tree[tIdx] = merge(tree[2 * tIdx + 1], tree[2 * tIdx + 2]);
+        };
+
+        f(0, 0, N - 1);
+    }
+
+
+    int query(int l, int r){
+
+        function<int(int, int , int)> f = [&](int tIdx, int tL, int tR){
+
+            // no overlap
+
+            if(tR < l || r < tL){
+                return identity;
+            }
+
+            // complete overlap
+
+            if(l <= tL && tR <= r   ){
+                return tree[tIdx];
+            }
+
+            // partial overlap
+            int tM = tL + (tR - tL) / 2;
+            return merge(f(2 * tIdx + 1, tL, tM), f(2 * tIdx + 2, tM + 1, tR));
+        };
+
+        return f(0, 0, N - 1);
+    }
+};
+void solve() {
+    int n, q; 
+    cin >> n >> q; 
+
+    segmentTree st(n, 0);
+
+    for(int i = 0; i < n; i++){
+        int x; cin >> x;
+        st.update(i, x);
+    }
+    while(q--){
+        int t, l, r;
+        cin >> t >> l >> r; 
+        if(t == 1){
+            st.update(l, r);
+        }
+        else
+            cout << st.query(l, r - 1) << endl;
+    }
+
+
+}
+
+signed main() {
+    fastio();
+    int t = 1;
+    while (t--) {
+        solve();
+    }
+    return 0;
+}