diff --git a/Luogu/CF438D/CF438D.cpp b/Luogu/CF438D/CF438D.cpp
new file mode 100644
index 00000000..408b002a
--- /dev/null
+++ b/Luogu/CF438D/CF438D.cpp
@@ -0,0 +1,99 @@
+#include <bits/stdc++.h>
+
+using std::cin;
+using std::cout;
+using std::endl;
+
+int n, m, op, l, r, x, a[100005];
+
+// Segment Tree
+void pushup(int);
+void build(int, int, int);
+void modify(int, int, int, int);
+void modify(int, int, int);
+long long query(int, int, int);
+
+signed main() {
+    std::ios::sync_with_stdio(false);
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+    build(1, 1, n);
+    while (m--) {
+        cin >> op >> l >> r;
+        if (op == 1) {
+            cout << query(1, l, r) << endl;
+        } else if (op == 2) {
+            cin >> x;
+            modify(1, l, r, x);
+        } else {
+            modify(1, l, r);
+        }
+    }
+    return 0;
+}
+
+// === Segment Tree ===
+
+struct node {
+    int l, r;
+    long long s, m;
+
+    node()
+        : l(0), r(0), s(0), m(0) {}
+    node(int _l, int _r)
+        : l(_l), r(_r), s(0), m(0) {}
+} tr[100005 << 2];
+
+inline void pushup(int u) {
+    tr[u].s = tr[u << 1].s + tr[u << 1 | 1].s;
+    tr[u].m = std::max(tr[u << 1].m, tr[u << 1 | 1].m);
+}
+
+void build(int u, int l, int r) {
+    tr[u] = node(l, r);
+    if (l == r) {
+        tr[u].s = tr[u].m = a[l];
+        return;
+    }
+    int mid = l + r >> 1;
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+    pushup(u);
+}
+
+void modify(int u, int x, int d) {
+    if (tr[u].l == x && tr[u].r == x) {
+        tr[u].s = tr[u].m = d;
+        return;
+    }
+    int mid = tr[u].l + tr[u].r >> 1;
+    if (x <= mid) {
+        modify(u << 1, x, d);
+    } else {
+        modify(u << 1 | 1, x, d);
+    }
+    pushup(u);
+}
+
+void modify(int u, int l, int r, int d) {
+    if (tr[u].m < d) return;
+    if (tr[u].l == tr[u].r) {
+        tr[u].s = tr[u].m %= d;
+        return;
+    }
+    int mid = tr[u].l + tr[u].r >> 1;
+    if (l <= mid) modify(u << 1, l, r, d);
+    if (r > mid) modify(u << 1 | 1, l, r, d);
+    pushup(u);
+}
+
+long long query(int u, int l, int r) {
+    if (l <= tr[u].l && tr[u].r <= r) return tr[u].s;
+    int mid = tr[u].l + tr[u].r >> 1;
+    long long sum = 0;
+    if (l <= mid) sum += query(u << 1, l, r);
+    if (r > mid) sum += query(u << 1 | 1, l, r);
+    return sum;
+}