You are given a license key represented as a string S which consists only alphanumeric character and dashes. The string is separated into N+1 groups by N dashes.
Given a number K, we would want to reformat the strings such that each group contains exactly K characters, except for the first group which could be shorter than K, but still must contain at least one character. Furthermore, there must be a dash inserted between two groups and all lowercase letters should be converted to uppercase.
Given a non-empty string S and a number K, format the string according to the rules described above.
Example 1:
Input: S = "5F3Z-2e-9-w", K = 4 Output: "5F3Z-2E9W" Explanation: The string S has been split into two parts, each part has 4 characters. Note that the two extra dashes are not needed and can be removed.
Example 2:
Input: S = "2-5g-3-J", K = 2 Output: "2-5G-3J" Explanation: The string S has been split into three parts, each part has 2 characters except the first part as it could be shorter as mentioned above.
Note:
/*** @param {string} S* @param {number} K* @return {string}*/var licenseKeyFormatting = function (S, K) {let res = "";let str = S.replace(/-/g, "");let groupLength = 0;for (let i = str.length - 1; i >= 0; i--) {res = str[i].toUpperCase() + res;if (++groupLength == K && i != 0) {res = "-" + res;groupLength = 0;}}return res;};let s = "2-5g-3-J";let k = 2;let res = licenseKeyFormatting(s, k);console.log(res);
482. License Key Formatting 格式化激活码
原文：http://www.cnblogs.com/xiejunzhao/p/8016419.html