diff --git "a/leetcode3/\354\240\225\354\247\204\354\230\201/3774. Absolute Difference Between Maximum and Minimum K Elements" "b/leetcode3/\354\240\225\354\247\204\354\230\201/3774. Absolute Difference Between Maximum and Minimum K Elements"
new file mode 100644
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--- /dev/null
+++ "b/leetcode3/\354\240\225\354\247\204\354\230\201/3774. Absolute Difference Between Maximum and Minimum K Elements"	
@@ -0,0 +1,16 @@
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number}
+ */
+var absDifference = function(nums, k) {
+    const arr = nums.sort((a, b) => a-b);
+    let sum1 = 0;
+    let sum2 = 0;
+    for(let i = 0; i<k; i++){
+        sum1 += arr[i];
+        sum2 += arr[arr.length-i-1];
+    }
+    let abs = sum2 - sum1;
+    return abs;
+};
diff --git "a/leetcode3/\354\240\225\354\247\204\354\230\201/870. Advantage Shuffle" "b/leetcode3/\354\240\225\354\247\204\354\230\201/870. Advantage Shuffle"
new file mode 100644
index 00000000..9e741332
--- /dev/null
+++ "b/leetcode3/\354\240\225\354\247\204\354\230\201/870. Advantage Shuffle"	
@@ -0,0 +1,39 @@
+/**
+ * @param {number[]} nums1
+ * @param {number[]} nums2
+ * @return {number[]}
+ */
+var advantageCount = function(nums1, nums2) {
+    // nums1 오름차순 정렬
+    nums1.sort((a, b) => a - b);
+
+    // nums2는 원래 위치와 함께 내림차순 정렬
+    const sortedNums2 = [];
+
+    for (let i = 0; i < nums2.length; i++) {
+        sortedNums2.push([nums2[i], i]);
+    }
+
+    sortedNums2.sort((a, b) => b[0] - a[0]);
+
+    const answer = new Array(nums1.length);
+    let left = 0;
+    let right = nums1.length - 1;
+
+    for (let i = 0; i < sortedNums2.length; i++) {
+        const value = sortedNums2[i][0];
+        const originalIndex = sortedNums2[i][1];
+
+        if (nums1[right] > value) {
+            // 이길 수 있으면 가장 큰 숫자로 이긴다
+            answer[originalIndex] = nums1[right];
+            right--;
+        } else {
+            // 가장 큰 숫자로도 못 이기면 가장 작은 숫자를 버린다
+            answer[originalIndex] = nums1[left];
+            left++;
+        }
+    }
+
+    return answer;
+};