[LeetCode 14] Longest Common Prefix

문제 바로가기

Description

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Write a function to find the longest common prefix string amongst an array of strings.

If there is no common prefix, return an empty string "".

Example 1

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• Input: strs = [“flower”,”flow”,”flight”]
• Output: “fl”

Example 2

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• Input: strs = [“dog”,”racecar”,”car”]
• Output: “”
• Explanation:
  • There is no common prefix among the input strings.

Constraints

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• 1 <= strs.length <= 200
• 0 <= strs[i].length <= 200
• strs[i] consists of only lowercase English letters if it is non-empty.

Code

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내 제출

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class Solution {
    public String longestCommonPrefix(String[] strs) {
        String result = strs[0];
        
        for(int i = 1; i < strs.length; i++){
            while(strs[i].indexOf(result) != 0){
                result = result.substring(0, result.length() - 1);
            }
        }
        return result;
    }
}

Runtime	Memory
0 ms	42 MB

다른 풀이

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class Solution {
    public String longestCommonPrefix(String[] v) {
        StringBuilder ans = new StringBuilder();
        Arrays.sort(v);
        String first = v[0];
        String last = v[v.length-1];
        for (int i=0; i<Math.min(first.length(), last.length()); i++) {
            if (first.charAt(i) != last.charAt(i)) {
                return ans.toString();
            }
            ans.append(first.charAt(i));
        }
        return ans.toString();
    }
}

Reference

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