algorithm_string_longest_common_prefix

algorithm_string_longest_common_prefix.java

public class Solution {
    public String longestCommonPrefix(String[] strs) {
        int leng = strs.length;
        if (leng == 0) return "";
        else if (leng == 1) return strs[0];
        
        // check the minimum length among all strings
        int minLen    = strs[0].length();
        String minStr = strs[0];
        for (int i = 1; i < leng; i++) {
            if (strs[i].length() < minLen) {
                minLen = strs[i].length();
                minStr = strs[i];
            }
        }
        
        for (int j = 0; j < minLen; j++) {
            char ch = strs[0].charAt(j);
            for (int k = 1; k < leng; k++) {
                char _ch = strs[k].charAt(j);
                if (ch != _ch) {
                    return minStr.substring(0, j);
                }
            }
        }
        return minStr;
    }
}

algorithm_string_longest_common_prefix.py

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        
        strsNum = len(strs)
        if   strsNum == 0: return ''
        elif strsNum == 1: return strs[0]
        
        # check the minimum length among all strings
        minLen, minStr = len(strs[0]), strs[0]
        for st in strs:
            if len(st) < minLen:
                minLen, minStr = len(st), st

        
        # check all string from one index to another
        for i in range(minLen):
            c = strs[0][i]
            for j in range(strsNum):
                _c = strs[j][i]
                if c != _c:
                    return minStr[0:i]
        return minStr