83 lines
1.9 KiB
Java
83 lines
1.9 KiB
Java
/*
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* @lc app=leetcode id=13 lang=java
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*
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* [13] Roman to Integer
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*/
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// @lc code=start
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import java.util.Arrays;
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class Solution {
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public int romanToInt(String s) {
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return romanToInt(0, s, 0);
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}
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private int romanToInt(int c, String s, int i) {
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if(i == s.length()) {
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return c;
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}
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int r;
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if(i+1 < s.length() && COMBINED_FORMAT_LIST.contains(s.substring(i, i+2))) {
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r = romanToInt(c+getValue(s.substring(i, i+2)), s, i+2);
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} else {
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r = romanToInt(c+getValue(s.substring(i, i+1)), s, i+1);
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}
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return r;
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}
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private int getValue(String s) {
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int r = 0;
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switch(s) {
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case "IV":
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r = 4;
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break;
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case "IX":
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r = 9;
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break;
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case "XL":
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r = 40;
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break;
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case "XC":
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r = 90;
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break;
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case "CD":
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r = 400;
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break;
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case "CM":
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r = 900;
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break;
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case "I":
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r = 1;
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break;
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case "V":
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r = 5;
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break;
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case "X":
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r = 10;
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break;
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case "L":
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r = 50;
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break;
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case "C":
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r = 100;
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break;
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case "D":
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r = 500;
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break;
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case "M":
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r = 1000;
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break;
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default:
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throw new RuntimeException("invalid expr: "+s);
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}
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return r;
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}
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public static final List<String> COMBINED_FORMAT_LIST = Arrays.asList(
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"IV","IX", "XL", "XC", "CD", "CM"
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);
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}
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// @lc code=end
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