More Easy

Question 1

Palindrome Number

Answer 1

x = 1221, return true
x = -1221, return false
x = 10, return false
https://leetcode.com/problems/palindrome-number/description/

// edge cases => negative case, ending in zero
Solution: reverse until half(even number of digits) or digit more than half(odd num of digits)

if reversedNum == x or reversedNum/10 == x => return true
if rversed nunber is equal ot first half of the number or first half excluding the mid, then its a palindrome

Question 2

Roman to Integer

Answer 2

Given roman number = III, what is integer = 3

start from right to left, take the last value
start a loop from the penultimate, call it current value, if current value < last value, subtract current val from current val. Otherwise add

move the current value

Question 3

Valid Parentheses

Answer 3

Use a map to store
map.put(‘]’, ‘[’);
map.put(‘}’, ‘{‘);
map.put(‘)’, ‘(‘);

if you find a closing brace while parsing the input, check if the stack has matching open brace. If not, return false
Otherwise, push it (as it must be an open brace)

if stack is empty, it must be valid parentheses
https://leetcode.com/problems/valid-parentheses/

Question 4

Valid word abbreviation

Answer 4

https://leetcode.com/problems/valid-word-abbreviation/submissions/1125493232/

internationalization
                   i            

i12iz4n
      j

number  = 0

numer = 12

if char proceed
if number, find the number, get to i + 1th index of the number

if i0iz4n - if number is zero, we return false

Question 5

Buildings with ocean view

Answer 5

https://leetcode.com/problems/buildings-with-an-ocean-view/submissions/1125507827/

Input: heights = [4,2,3,1]
Output: [0,2,3]
Explanation: Building 1 (0-indexed) does not have an ocean view because building 2 is taller.

start from right, maintain a maxheightsofar
last building with always have a view and make maxheightsofar as the last building
from there while traversing left, check if the val is less than