Add some code

leetcode/problems/java/check-if-array-pairs-are-divisible-by-k.java

@@ -0,0 +1,16 @@
+class Solution {
+  public boolean canArrange(int[] arr, int k) {
+    int freq[] = new int[k];
+    for (int n : arr)
+      freq[(n % k + k) % k]++;
+
+    if (freq[0] % 2 != 0) // k - 0 = k and it does not exist in the array
+      return false;
+
+    for (int i = 1; i <= k / 2; i++)
+      if (freq[i] != freq[k - i])
+        return false;
+
+    return true;
+  }
+}