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+Follow up for "Remove Duplicates":
+What if duplicates are allowed at most *twice*?
+
+For example,
+Given sorted array *nums* = `[1,1,1,2,2,3]`,
+
+Your function should return length = `5`, with the first five elements of nums being `1`, `1`, `2`, `2` and `3`. It doesn't matter what you leave beyond the new length.
@@ -0,0 +1,31 @@
+public class Solution {
+    public int removeDuplicates(int[] nums) {
+        if (nums == null || nums.length == 0)
+            return 0;
+        
+        int slowIdx = 0;
+        int fastIdx = 0;
+        int cnt = 0;
+        
+        int idx = 0;
+        while (fastIdx < nums.length) {
+            while (fastIdx < nums.length && nums[slowIdx] == nums[fastIdx]) {
+                fastIdx++;
+            }
+            
+            if (slowIdx != fastIdx - 1) {
+                nums[idx++] = nums[slowIdx];
+                nums[idx++] = nums[fastIdx - 1];
+                cnt += 2;
+                
+                slowIdx = fastIdx;
+            } else {
+                nums[idx++] = nums[slowIdx];
+                slowIdx = fastIdx;
+                cnt++;
+            }
+        }
+        
+        return cnt;
+    }
+}