longest-common-prefix.java

// 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:
//
//
// Input: strs = ["flower","flow","flight"]
// Output: "fl"
//
//
// Example 2:
//
//
// Input: strs = ["dog","racecar","car"]
// Output: ""
// Explanation: There is no common prefix among the input strings.
//
//
//  
// Constraints:
//
//
// 	0 <= strs.length <= 200
// 	0 <= strs[i].length <= 200
// 	strs[i] consists of only lower-case English letters.
//
//


class Solution {
    public String longestCommonPrefix(String[] strs) {
        if (strs.length == 0) return "";
        StringBuilder sb = new StringBuilder(strs[0]);
        for (int i=1;i<strs.length;i++){
            while (!strs[i].startsWith(sb.toString())) sb.deleteCharAt(sb.length()-1);
        }
        return sb.toString();
    }
}