标签:tee sim har .com problems 代码 add from action
https://leetcode.com/problems/roman-to-integer/description/
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.
Example 1:
Input: "III" Output: 3
Example 2:
Input: "IV" Output: 4
Example 3:
Input: "IX" Output: 9
Example 4:
Input: "LVIII" Output: 58 Explanation: L = 50, V= 5, III = 3.
Example 5:
Input: "MCMXCIV" Output: 1994 Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
代码:
class Solution { public: int romanToInt(string s) { int val[10] = {1, 5, 10, 50, 100, 500, 1000}; map<char, int> mp; mp[‘I‘] = 1; mp[‘V‘] = 5; mp[‘X‘] = 10; mp[‘L‘] = 50; mp[‘C‘] = 100; mp[‘D‘] = 500; mp[‘M‘] = 1000; int len = s.length(); int ans = mp[s[len - 1]]; int cnt = mp[s[len - 1]]; for(int i = len - 2; i >= 0; i --) { if(mp[s[i]] < cnt) ans = ans - mp[s[i]]; else ans += mp[s[i]]; cnt = mp[s[i]]; } return ans; } };
#Leetcode# 13. Roman to Integer
标签:tee sim har .com problems 代码 add from action
原文地址:https://www.cnblogs.com/zlrrrr/p/9898497.html