create segment.cpp

segment.cpp

@@ -0,0 +1,98 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define ll long long
+
+struct segmenttree {
+    int n;
+    vector<int> st;
+
+    void init(int _n) {
+        this->n = _n;
+        st.resize(4 * _n, 0);
+    }
+
+    void build(int start, int end, int node, vector<int> &v) {
+        if (start == end) {
+            st[node] = v[start];
+            return;
+        }
+        int mid = (start + end) / 2;
+
+        // left subtree : [start, mid]
+        build(start, mid, 2 * node + 1, v);
+
+        // right subtree : [mid+1, end]
+        build(mid + 1, end, 2 * node + 2, v);
+
+        // IMPORTANT : compute for current node
+        st[node] = st[2 * node + 1] ^ st[2 * node + 2];
+    }
+
+    int query(int start, int end, int l, int r, int node) {
+        if (start > r || end < l) { // Non overlapping
+            // IMPORTANT : return something that won't affect the ans
+            return 0;
+        }
+
+        if (start >= l && end <= r) {   // completely overlapping
+            return st[node];
+        }
+        // Partial overlapping
+        int mid = (start + end) / 2;
+        int q1 = query(start, mid, l, r, 2 * node + 1);
+        int q2 = query(mid + 1, end, l, r, 2 * node + 2);
+        // compute query ans
+        return q1 ^ q2;
+    }
+
+
+    void update(int start, int end, int node, int idx, int val) {
+        if (start == end) {
+            st[node] = val;
+            return;
+        }
+        int mid = (start + end) / 2;
+        if (idx <= mid) {   // Left subtree
+            update(start, mid, 2 * node + 1, idx, val);
+        } else {            // Right subtree
+            update(mid + 1, end, 2 * node + 2, idx, val);
+        }
+        // making changes to nodes
+        st[node] = st[2 * node + 1] ^ st[2 * node + 2];
+    }
+
+
+    void build(vector<int> &v) {
+        build(0, n - 1, 0, v);
+    }
+
+    int query(int l, int r) {
+        return query(0, n - 1, l, r, 0);
+    }
+
+    void update(int idx, int val) {
+        update(0, n - 1, 0, idx, val);
+    }
+
+};
+// elements
+// 1 2 3 2
+// [1,3] 1 2 3
+// 3
+int main() {
+    ios_base::sync_with_stdio(0);
+    cin.tie(0); cout.tie(0);
+
+
+    int n;
+    cin >> n;
+    vector<int> array(n);
+    for (auto &ai : array) {
+        cin >> ai;
+    }
+    segmenttree tree;
+    tree.init(n);
+    tree.build(array);
+
+    return 0;
+}