feat: add 012

Author: Blankj

Diff for: README.md

@@ -73,6 +73,7 @@
 | 6    | [ZigZag Conversion][006]                 | String                           |
 | 8    | [String to Integer (atoi)][008]          | Math, String                     |
 | 11   | [Container With Most Water][011]         | Array, Two Pointers              |
+| 12   | [Integer to Roman][012]                  | Math, String                     |
 | 15   | [3Sum][015]                              | Array, Two Pointers              |
 | 17   | [Letter Combinations of a Phone Number][017] | String, Backtracking             |
 | 19   | [Remove Nth Node From End of List][019]  | Linked List, Two Pointers        |
@@ -143,6 +144,7 @@
 [006]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/006/README.md
 [008]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/008/README.md
 [011]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/011/README.md
+[012]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/012/README.md
 [015]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/015/README.md
 [017]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/017/README.md
 [019]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/019/README.md

Diff for: note/012/README.md

@@ -0,0 +1,44 @@
+# [Container With Most Water][title]
+
+## Description
+
+Given an integer, convert it to a roman numeral.
+
+Input is guaranteed to be within the range from 1 to 3999.
+
+**Tags:** Math, String
+
+
+## 思路
+
+题意是整型数转罗马数字，范围从 1 到 3999，查看下百度百科的罗马数字介绍如下：
+
+* 相同的数字连写，所表示的数等于这些数字相加得到的数，如 Ⅲ=3；
+
+* 小的数字在大的数字的右边，所表示的数等于这些数字相加得到的数，如 Ⅷ=8、Ⅻ=12；
+
+* 小的数字（限于 Ⅰ、X 和 C）在大的数字的左边，所表示的数等于大数减小数得到的数，如 Ⅳ=4、Ⅸ=9。
+
+那么我们可以把整数的每一位分离出来，让其每一位都用相应的罗马数字位表示，最终拼接完成。比如 `621` 我们可以分离百、十、个分别为 `6`、`2`、`1`，那么 `600` 对应的罗马数字是 `DC`，`20` 对应的罗马数字是 `XX`，`1` 对应的罗马数字是 `I`，所以最终答案便是 `DCXXI`。
+
+```java
+class Solution {
+    public String intToRoman(int num) {
+        String M[] = {"", "M", "MM", "MMM"};
+        String C[] = {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"};
+        String X[] = {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
+        String I[] = {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};
+        return M[num / 1000] + C[(num % 1000) / 100] + X[(num % 100) / 10] + I[num % 10];
+    }
+}
+```
+
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-java-leetcode][ajl]
+
+
+
+[title]: https://leetcode.com/problems/container-with-most-water
+[ajl]: https://github.com/Blankj/awesome-java-leetcode

Diff for: src/com/blankj/medium/_012/Solution.java

@@ -0,0 +1,25 @@
+package com.blankj.medium._012;
+
+/**
+ * <pre>
+ *     author: Blankj
+ *     blog  : http://blankj.com
+ *     time  : 2018/01/25
+ *     desc  :
+ * </pre>
+ */
+public class Solution {
+    public String intToRoman(int num) {
+        String M[] = {"", "M", "MM", "MMM"};
+        String C[] = {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"};
+        String X[] = {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
+        String I[] = {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};
+        return M[num / 1000] + C[(num % 1000) / 100] + X[(num % 100) / 10] + I[num % 10];
+    }
+
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        System.out.println(solution.intToRoman(621));// DCXXI
+        System.out.println(solution.intToRoman(348));// CCCXLVIII
+    }
+}