diff --git a/Luogu/P3901/P3901.cpp b/Luogu/P3901/P3901.cpp
new file mode 100644
index 00000000..44d95fbd
--- /dev/null
+++ b/Luogu/P3901/P3901.cpp
@@ -0,0 +1,71 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <tuple>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, q, a[N], c[N], t;
+bool ans[N];
+std::vector<std::tuple<int, int, int>> qs;
+
+inline void add(int x, int &res) {
+    if (!c[x]++) res++;
+}
+
+inline void del(int x, int &res) {
+    if (!--c[x]) res--;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> q;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    t = sqrt(n);
+
+    for (int i = 1, l, r; i <= q; i++) {
+        cin >> l >> r;
+
+        qs.push_back(std::make_tuple(i, l, r));
+    }
+
+    std::sort(qs.begin(), qs.end(), [&](auto a, auto b) {
+        int p = std::get<1>(a) / t,
+            q = std::get<1>(b) / t;
+
+        return p == q
+                 ? (p & 1)
+                     ? std::get<2>(a) < std::get<2>(b)
+                     : std::get<2>(a) > std::get<2>(b)
+                 : p < q;
+    });
+
+    int i = 0, j = 1, res = 0, x, l, r;
+    for (auto q : qs) {
+        std::tie(x, l, r) = q;
+
+        while (i < r) add(a[++i], res);
+        while (i > r) del(a[i--], res);
+        while (j < l) del(a[j++], res);
+        while (j > l) add(a[--j], res);
+
+        ans[x] = res == (r - l + 1);
+    }
+
+    for (int i = 1; i <= q; i++) {
+        cout << (ans[i] ? "Yes" : "No") << endl;
+    }
+
+    return 0;
+}
diff --git a/Luogu/P3901/data/P3901_6.in b/Luogu/P3901/data/P3901_6.in
new file mode 100644
index 00000000..a8f68d86
--- /dev/null
+++ b/Luogu/P3901/data/P3901_6.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:28234ac4abf554f2a88292aa4fb2426f48936620287dfcc005e04deefdc6e034
+size 1346189
diff --git a/Luogu/P3901/data/P3901_6.out b/Luogu/P3901/data/P3901_6.out
new file mode 100644
index 00000000..5e147091
--- /dev/null
+++ b/Luogu/P3901/data/P3901_6.out
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:cd92de1a9dbb8a0be379908c1d1395602e2b760effd11a683c5bacdae5c29030
+size 278000
diff --git a/Luogu/P3901/data/P3901_8.in b/Luogu/P3901/data/P3901_8.in
new file mode 100644
index 00000000..17e0e51a
--- /dev/null
+++ b/Luogu/P3901/data/P3901_8.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:dc853ae36c080bbf3677213fd8ced59d494215ddd89765738902ec65e3d1ddb8
+size 1657161
diff --git a/Luogu/P3901/data/P3901_8.out b/Luogu/P3901/data/P3901_8.out
new file mode 100644
index 00000000..de567296
--- /dev/null
+++ b/Luogu/P3901/data/P3901_8.out
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:45983447eb4f85d4cae4ac838d3987bff178e865375ab19a790b52487bcec1e1
+size 292204