diff --git "a/khj20006/202511/25 BOJ P4 \354\223\260\353\213\264\354\223\260\353\213\264.md" "b/khj20006/202511/25 BOJ P4 \354\223\260\353\213\264\354\223\260\353\213\264.md"
new file mode 100644
index 00000000..7645c71c
--- /dev/null
+++ "b/khj20006/202511/25 BOJ P4 \354\223\260\353\213\264\354\223\260\353\213\264.md"	
@@ -0,0 +1,47 @@
+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+
+int N, Q;
+int seg[262144]{}, height[100001]{};
+
+void upt(int s, int e, int i, int n) {
+    if(s == e) {
+        if(s == N || height[s] <= height[s+1]) seg[n] = 0;
+        else seg[n] = 1;
+        return;
+    }
+    int m = (s+e)>>1;
+    if(i <= m) upt(s,m,i,n<<1);
+    else upt(m+1,e,i,n<<1|1);
+    seg[n] = seg[n<<1] + seg[n<<1|1];
+}
+
+int find(int s, int e, int l, int r, int n) {
+    if(l>r || l>e || r<s) return 0;
+    if(l<=s && e<=r) return seg[n];
+    int m = (s+e)>>1;
+    return find(s,m,l,r,n<<1) + find(m+1,e,l,r,n<<1|1);
+}
+
+int main(){
+    cin.tie(0)->sync_with_stdio(0);
+
+    cin>>N>>Q;
+    for(int i=1;i<=N;i++) cin>>height[i];
+    for(int i=1;i<=N;i++) upt(1,N,i,1);
+
+    for(int o,l,r;Q--;) {
+        cin>>o>>l>>r;
+        if(o == 1) cout<<(find(1,N,l,r-1,1) ? "HSS090\n": "CS204\n");
+        else {
+            swap(height[l], height[r]);
+            if(l>1) upt(1,N,l-1,1);
+            upt(1,N,l,1);
+            if(r>1) upt(1,N,r-1,1);
+            upt(1,N,r,1);
+        }
+    }
+
+}
+```