diff --git a/Luogu/P3834/P3834.cpp b/Luogu/P3834/P3834.cpp
index 30802c03..ee1af48b 100644
--- a/Luogu/P3834/P3834.cpp
+++ b/Luogu/P3834/P3834.cpp
@@ -1,5 +1,6 @@
 #include <iostream>
 #include <algorithm>
+#include <iterator>
 #include <vector>
 
 using std::cin;
@@ -16,12 +17,16 @@ struct node {
     int l, r, c;
 } tr[N << 5];
 
+int find(int x) {
+    return std::distance(nums.begin(), std::lower_bound(nums.begin(), nums.end(), x));
+}
+
 int build(int l, int r) {
     int p = ++cnt;
 
     if (l == r) return p;
 
-    int mid = l + r >> 1;
+    int mid = (l + r) >> 1;
 
     tr[p].l = build(l, mid);
     tr[p].r = build(mid + 1, r);
@@ -31,30 +36,35 @@ int build(int l, int r) {
 
 int insert(int p, int l, int r, int x) {
     int q = ++cnt;
+
     tr[q] = tr[p];
 
     if (l == r) {
         tr[q].c++;
+
         return q;
     }
 
-    int mid = l + r >> 1;
+    int mid = (l + r) >> 1;
 
-    if (x <= mid) tr[q].l = insert(tr[q].l, l, mid, x);
-    else tr[q].r = insert(tr[q].r, mid + 1, r, x);
+    if (x <= mid) tr[q].l = insert(tr[p].l, l, mid, x);
+    else tr[q].r = insert(tr[p].r, mid + 1, r, x);
 
     tr[q].c = tr[tr[q].l].c + tr[tr[q].r].c;
 
     return q;
 }
 
-int query(int p, int q, int l, int r, int x) {
+int query(int p, int q, int l, int r, int k) {
     if (l == r) return l;
-    int c = tr[tr[p].l].c - tr[tr[q].l].c;
-    int mid = l + r >> 1;
 
-    if (x <= c) return query(tr[p].l, tr[q].l, l, mid, x);
-    return query(tr[p].r, tr[q].r, mid + 1, r, x - c);
+    int mid = (l + r) >> 1;
+
+    int c = tr[tr[q].l].c - tr[tr[p].l].c;
+
+    if (c >= k) return query(tr[p].l, tr[q].l, l, mid, k);
+
+    return query(tr[p].r, tr[q].r, mid + 1, r, k - c);
 }
 
 int main() {
@@ -75,7 +85,7 @@ int main() {
     root[0] = build(0, nums.size() - 1);
 
     for (int i = 1; i <= n; i++) {
-        root[i] = insert(root[i - 1], 0, nums.size() - 1, std::lower_bound(nums.begin(), nums.end(), a[i]) - nums.begin());
+        root[i] = insert(root[i - 1], 0, nums.size() - 1, find(a[i]));
     }
 
     while (m--) {
@@ -83,7 +93,7 @@ int main() {
 
         cin >> l >> r >> k;
 
-        cout << nums.at(query(root[r], root[l - 1], 0, nums.size() - 1, k)) << endl;
+        cout << nums[query(root[l - 1], root[r], 0, nums.size() - 1, k)] << endl;
     }
 
     return 0;