diff --git a/src/10/18/P9015.cpp b/src/10/18/P9015.cpp
new file mode 100644
index 0000000..fcfa794
--- /dev/null
+++ b/src/10/18/P9015.cpp
@@ -0,0 +1,57 @@
+#include <cstdint>
+#include <cstdio>
+#include <iostream>
+#include <istream>
+using ll = int64_t;
+
+const ll maxn = 1e5+5;
+ll n;
+ll a[maxn];
+
+
+int main(){
+    std::iostream::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin>>n;
+    for(ll i=1;i<=n;i++){
+        std::cin>>a[i];
+    }
+    ll now=0;
+    ll dir=1;
+    while (1) {
+        if(now==0 && dir==-1){//往左走走到头
+            if(a[1]==0)break;
+            dir=1;
+            continue;
+        }
+        if(now==n && dir==1){//往右走走走到头
+            dir=-1;
+            continue;
+        }
+        if(dir==1){
+            if(a[now+1]==0){
+                dir=-1;
+                continue;
+            }
+            putchar('R');
+            now++;
+            a[now]--;
+        }else{
+            if(a[now]==1){
+                if(a[now+1]==0){
+                    putchar('L');
+                    a[now]--;
+                    now--;
+                }else{
+                    dir=1;
+                }
+            }else{
+                putchar('L');
+                a[now]--;
+                now--;
+            }
+        }
+    }
+    putchar(*"\n");
+}
\ No newline at end of file