feat: add question 1338

Author: yinxin630

1338.数组大小减半.js

@@ -0,0 +1,33 @@
+/**
+ * @param {number[]} arr
+ * @return {number}
+ */
+var minSetSize = function(arr) {
+    const map = {};
+    for (const n of arr) {
+        map[n] = map[n] || 0;
+        map[n]++;
+    }
+
+    let sum = 0;
+    const list = Object.keys(map).map(n => {
+        sum += map[n];
+        return {
+            n,
+            c: map[n]
+        }
+    })
+
+    list.sort((a, b) => b.c - a.c)
+
+    let result = 0;
+    let current = sum;
+    for (const a of list) {
+        result++;
+        current -= a.c;
+        if (current * 2 <= sum) {
+            break;
+        }
+    }
+    return result;
+};