LeetCode Questions
- 1 two sum
- 2 add two numbers
- 3 longest substring without repeating characters
- 4 median of two sorted arrays
- 5 longest palindromic substring
- 6 two sum
- 7 reverse integer
- 8 palindrome number
- 9 roman to integer
- 10 longest common prefix
- 11 container with most water
- 12 integer to roman
- 13 roman to integer
- 14 longest common prefix
- 15 3sum
- 16 3sum closest
- 17 letter combinations of a phone number
- 18 4sum
- 19 remove nth node from end of list
- 20 valid parentheses
- 21 merge two sorted lists
- 22 generate parentheses
- 23 merge k sorted lists
- 24 swap nodes in pairs
- 25 reverse nodes in k group
- 26 remove duplicates from sorted array
- 27 remove element
- 28 implement strstr
- 29 divide two integers
- 30 substring with concatenation of all words
- 31 next permutation
- 32 longest valid parentheses
- 33 search in rotated sorted array
- 34 find first and last position of element in sorted array
- 35 search insert position
- 36 valid sudoku
- 37 sudoku solver
- 38 count and say
- 39 combination sum
- 40 combination sum ii
- 41 first missing positive
- 42 trapping rain water
- 43 multiply strings
- 44 wildcard matching
- 45 jump game ii
- 46 permutations
- 47 permutations ii
- 48 rotate image
- 49 group anagrams
- 50 powx n
13. Roman to Integer
Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, which is simply X + II. The number twenty seven is written as XXVII, which is XX + V + II. Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used: - I can be placed before V (5) and X (10) to make 4 and 9. - X can be placed before L (50) and C (100) to make 40 and 90. - C can be placed before D (500) and M (1000) to make 400 and 900. Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.
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