## Question 1 What is the output if four **Pop()** calls are made onto this stack?

### Options 1. [5, 4, 7, 5] Incorrect ---------------------------- 2. [5, 7, 4, 5] Incorrect ---------------------------- 3. [7, 5, 4, 7] Correct $7$ and $5$ both appear $3$ times in this stack. The number that is close to or equal to the top of the stack is removed first, that is $7$, and then rest of the remaining $3$ numbers are popped. ---------------------------- --------------------------------------------- ## Question 2 What is the output if five **Pop()** calls are made onto this stack?

### Options 1. [3, 9, 6, 3, 6] Correct Frequency of $3$ is greater than any other, so it is popped first, then, $3, 6$ and $9$, all appear $3$ times. The number that was pushed most recently in the stack will be popped off, in this case, $9$, and so on. ---------------------------- 2. [3, 6, 9, 3, 6] Incorrect ---------------------------- 3. [3, 9, 6, 9, 6] Incorrect ---------------------------- --------------------------------------------- ## Question 3 What is the output if three **Pop()** calls are made onto this stack?

### Options 1. [2, 8, 5] Incorrect ---------------------------- 2. [8, 2, 1] Incorrect ---------------------------- 3. [8, 2, 5] Correct $8$ and $2$, both appear $2$ times in the stack. The most recently pushed number, that is, $8$, will be popped off first and then the remaining numbers. ---------------------------- ---------------------------------------------