Create segtree.cc

trees/segtree.cc

@@ -0,0 +1,47 @@
+template<typename T> class segtree {
+private:
+    using size_type = __uint64_t;
+    T _max;
+    vector<T> d, b;
+
+    void _update(size_type s, size_type t, size_type p, size_type l, size_type r, T c) {
+        if (l <= s && t <= r) {
+            d[p] += c * (t - s + 1);
+            b[p] += c;
+            return;
+        }
+        size_type m = s + (t - s >> 1);
+        if (b[p] && s != t) {
+            d[p * 2] += b[p] * (m - s + 1), d[p * 2 + 1] += b[p] * (t - m);
+            b[p * 2] += b[p], b[p * 2 + 1] += b[p];
+            b[p] = 0;
+        }
+        if (l <= m) _update(s, m, p * 2, l, r, c);
+        if (r > m)  _update(m + 1, t, p * 2 + 1, l, r, c);
+        d[p] = d[p * 2] + d[p * 2 + 1];
+    }
+
+    T _query(size_type s, size_type t, size_type p, size_type l, size_type r) {
+        if (l <= s && t <= r) return d[p];
+        size_type m = s + (t - s >> 1);
+        T res = {};
+        if (b[p]) {
+            d[p * 2] += b[p] * (m - s + 1), d[p * 2 + 1] += b[p] * (t - m);
+            b[p * 2] += b[p], b[p * 2 + 1] += b[p];
+            b[p] = 0;
+        }
+        if (l <= m) res += _query(s, m, p * 2, l, r);
+        if (r > m)  res += _query(m + 1, t, p * 2 + 1, l, r);
+        return res;
+    }
+public:
+    segtree(T _max) : d(4 * _max, {}), b(4 * _max, {}), _max(_max) {}
+
+    void update(size_type l, size_type r, T c) {
+        _update({}, _max, 1, l, r, c);
+    }
+
+    T query(size_type l, size_type r) {
+        return _query({}, _max, 1, l, r);
+    }
+};