419

2017.10.27

public class Solution {    /*     * @param s: Roman representation     * @return: an integer     */public int romanToInt(String s){HashMap<Character,Integer> map = new HashMap<>();map.put('I', 1);map.put('X', 10);map.put('C', 100);map.put('M', 1000);map.put('V', 5);map.put('L', 50);map.put('D', 500);if(s.length() == 0){return 0;}if(s.length() == 1){return map.get(s.charAt(0));}int res = 0;for(int i = s.length()-1; i >= 0; i--){char c = s.charAt(i);if(c == 'I' || c == 'X' || c == 'C'){    if(i == s.length() - 1){res = res + map.get(c);} else if(map.get(c) < map.get(s.charAt(i+1))){res = res - map.get(c);}else {res = res + map.get(c);}}else{res = res + map.get(c);}}return res;}}