diff --git "a/leetcode3/\355\231\251\354\235\200\354\247\200/315. Count of Smaller Numbers After Self.js" "b/leetcode3/\355\231\251\354\235\200\354\247\200/315. Count of Smaller Numbers After Self.js"
new file mode 100644
index 00000000..a6eeddb6
--- /dev/null
+++ "b/leetcode3/\355\231\251\354\235\200\354\247\200/315. Count of Smaller Numbers After Self.js"	
@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var countSmaller = function (nums) {
+  const output = Array(nums.length);
+  // 이렇게 하니까 잘못 참조 함..
+  for (let i = nums.length - 1; i >= 0; i--) {
+    output[i] = 0;
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[j] <= nums[i]) {
+        if (nums[j] === nums[i]) output[i] = output[j];
+        else output[i] = output[j] + 1;
+        break;
+      }
+    }
+  }
+
+  return output;
+};