**We should consider Q2 to be an array of size greater than length 4, then only the answer will come.**

Step 0: Enqueue 1 in Q2, it is already sorted,

Step 1: Enqueue 2 in Q2 i.e **1,2**

Step 2: perform 1 dequeue and 1 enqueue simultaneously for 1 time in Q2 i.e **2,1 (Head is pointing at 2)**

Step 3: enqueue 3 in Q2 i.e **2,1,3**

Step 4: perform 1 dequeue and 1 enqueues in simultaneously for 2 times in Q2 i.e** 2,1,3 → 1,3,2 → 3,2,1 (head pointing at 3 now)**

Step 5: Enqueue 4 in Q2 i.e **3,2,1,4**

Step 6: perform 1 dequeue and 1 enqueues in simultaneously for 3 times in Q2 i.e 3**,2,1,4 → 2,1,4,3 → 1,4,3,2 → 4,3,2,1**

**So the number of enqueue operations in Q1 is 0.**

The question was bad in the sense that it didn’t say that the array size of Q2 is greater than 4 so solving conventionally with rear and front keeping the size limitation will not work same with the case if we consider it a circular queue.