Longest Common Prefix

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

首先判断最小长度，然后就是遍历。记得内部循环后置零

public String longestCommonPrefix(String[] strs) {
        if (strs.length==0){
            return "";
        }
        if (strs.length==1){
            return strs[0];
        }
        int i=1;
        int j=0;
        int minlength = Integer.MAX_VALUE;
        for (int a=0;a<strs.length;a++){
            minlength = minlength>strs[a].length()?strs[a].length():minlength;
        }
        StringBuilder stringBuilder = new StringBuilder();
        while(j<minlength){
            while (i<strs.length){
                if (strs[i].charAt(j)!=strs[0].charAt(j)){
                    if (stringBuilder.length()!=0){
                        return stringBuilder.toString();
                    }
                    else{
                        return "";
                    }
                }
                i++;
            }
            stringBuilder.append(strs[0].charAt(j));
            j++;
            i=1;
        }
        return stringBuilder.toString();
    }