LeetCode解题报告--Longest Common Prefix

2019年11月3日 238次阅读

题目：最长公共前缀
Write a function to find the longest common prefix string amongst an array of strings.

分析：题意找出所有字符串的最长公共前缀。 思路简单：如下步骤
1. 找出字符串数组中字符串长度最小的字符串minStr
2. minStr与其余的字符串逐个字符比较，确定最长公共前缀

java 代码：（accepted）

public class LongestCommonPrefix {

    /** * @param args */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String[] strs = new String[]{"aabd","aabcd","aaccs","aa"};
        System.out.println("Longest Common Prefix: " + longestCommonPrefix(strs));
        String[] strs1 = new String[]{"a","b"};
        System.out.println("Longest Common Prefix 1: " + longestCommonPrefix(strs1));
        String[] strs2 = new String[]{"",""};
        System.out.println("Longest Common Prefix 2: " + longestCommonPrefix(strs2));
        String[] strs3 = new String[]{"ssa","ssab"};
        System.out.println("Longest Common Prefix 3: " + longestCommonPrefix(strs3));
        String[] strs4 = new String[]{"","b"};
        System.out.println("Longest Common Prefix 4: " + longestCommonPrefix(strs4));
        String[] strs5 = new String[]{"leet","left","leave","leat"};
        System.out.println("Longest Common Prefix 5: " + longestCommonPrefix(strs5));
    }

    public static String longestCommonPrefix(String[] strs) {
        String minStr = "";
        int minLength = Integer.MAX_VALUE;

        if(strs.length == 1)
            return strs[0];
        else if(strs.length == 0)
            return "";
        //Find the smallest length
        for(int i = 0;i < strs.length;i ++){
            if(strs[i].length() < minLength){
                minStr = strs[i];
                minLength = strs[i].length();
            }
        }

        for(int i = 0;i < strs.length;i ++){
            int j;
            for(j = 0;j < minLength;j ++){
                if(minStr.charAt(j) != strs[i].charAt(j)){
                    break;
                }
            }
            if(j < minLength)
                minLength = j;
        }
        return minStr.substring(0,minLength);
    }
}

测试结果：

Longest Common Prefix: aa
Longest Common Prefix 1: 
Longest Common Prefix 2: 
Longest Common Prefix 3: ssa
Longest Common Prefix 4: 
Longest Common Prefix 5: le

相关代码放在个人github:https://github.com/gannyee/LeetCode/tree/master/src

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