data-structures-stacks

Question 1

What does the acronym LIFO mean?

Answer 1

last in first out

Question 2

What methods are available on a Stack data structure?

Answer 2

push, pop, print, peek

Question 3

What must you do to access the value at an arbitrary point in a stack (not just the “top”)?

Answer 3

continuously pop until you reach that point in the stack

Question 4

Are braces balanced (interview question: algo challenge)
- take a string containing brackets, braces, parentheses,
- return boolean to say if the string’s braces are balanced

• balanced example: {[[()]]}
• unbalanced example: [{)]

Answer 4

solution
- for each char, check if opening brace
- if yes, push it on to stack
- if closing brace,
- if the stack’s top is matching opening brace, pop it
- if the stack’s top is not matching return false