g0401_0500.s0482_license_key_formatting.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0401_0500.s0482_license_key_formatting;

// #Easy #String #2022_07_20_Time_8_ms_(96.52%)_Space_45.4_MB_(58.75%)

/**
 * 482 - License Key Formatting\.
 *
 * Easy
 *
 * You are given a license key represented as a string `s` that consists of only alphanumeric characters and dashes. The string is separated into `n + 1` groups by `n` dashes. You are also given an integer `k`.
 *
 * We want to reformat the string `s` 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 you should convert all lowercase letters to uppercase.
 *
 * Return _the reformatted license key_.
 *
 * **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.
 *
 * **Constraints:**
 *
 * *   1 <= s.length <= 10⁵
 * *   `s` consists of English letters, digits, and dashes `'-'`.
 * *   1 <= k <= 10⁴
**/
public class Solution {
    public String licenseKeyFormatting(String s, int k) {
        StringBuilder sb = new StringBuilder();
        int cnt = 0;
        int occ = 0;
        for (char c : s.toCharArray()) {
            if (c == '-') {
                continue;
            }
            cnt++;
        }
        int l = cnt % k;
        for (char c : s.toCharArray()) {
            if (c == '-') {
                continue;
            }
            if (occ == k) {
                occ = 0;
                sb.append('-');
            } else if (occ == l && l != 0) {
                l = 0;
                occ = 0;
                sb.append('-');
            }
            sb.append(Character.toUpperCase(c));
            occ++;
        }
        return sb.toString();
    }
}