License Key Formatting Problem
Description
LeetCode Problem 482.
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:
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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:
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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 <= 10^5
- s consists of English letters, digits, and dashes ‘-‘.
- 1 <= k <= 10^4
Sample C++ Code
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class Solution {
public:
string licenseKeyFormatting(string S, int K) {
int len = S.size();
string newS = "";
int count = 0;
for (int i = len - 1; i >= 0; i --) {
if (S[i] == '-')
continue;
if (count == K) {
newS += '-';
count = 0;
}
count ++;
newS += toupper(S[i]);
}
reverse(newS.begin(), newS.end());
return newS;
}
};