Given a string array words, find the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. You may assume that each word will contain only lower case letters. If no such two words exist, return 0.

Example 1:


Given ["abcw", "baz", "foo", "bar", "xtfn", "abcdef"]
 Return 16
 The two words can be "abcw", "xtfn".

Example 2:


Given ["a", "ab", "abc", "d", "cd", "bcd", "abcd"]
 Return 4
 The two words can be "ab", "cd".

Example 3:


Given ["a", "aa", "aaa", "aaaa"]
 Return 0
 No such pair of words.

在编程中，通常比较两个字符串是否相同的表达式是“==”,但在java中不能这么写。在java中，用的是equals();
例：A字符串和B和字符串比较:
if(A.equals(B)){
}
返回true 或false.
String 的equals 方法用于比较两个字符串是否相等。由于字符串是对象类型，所以不能用简单的“==”判断。而使用equals比较两个对象的内容是否相等。
注意：
equals()比较的是对象的内容（区分字母的大小写格式），但是如果使用“==”比较两个对象时，比较的是两个对象的内存地址，所以不相等。即使它们内容相等，但是不同对象的内存地址也是不相同的。

package handleString;

public class HandleString {

    String[] sg1 = { "abcw", "baz", "foo", "bar", "xtfn", "abcdef" };
    String[] sg2 = { "a", "ab", "abc", "d", "cd", "bcd", "abcd" };
    String[] sg3 = { "a", "aa", "aaa", "aaaa" };

    public int stringArrayCompare(String[] a) {
        int value = 0;
        for (int i = 0; i < a.length; i++) {
            for (int j = i + 1; j < a.length; j++) {
                if (compare(a[i], a[j])) {
                    int temp = a[i].length() * a[j].length();
                    if (temp > value) {
                        value = temp;
                    }
                } else {
                    continue;
                }
            }
        }
        return value;
    }

    // 如果两个字符串有相等的值则返回 false, 无相同值返回true;
    public boolean compare(String f, String s) {

        for (int i = 0; i < f.length(); i++) {
            for (int j = 0; j < s.length(); j++) {
                if (f.charAt(i) == s.charAt(j)) {
                    return false;
                }
            }
        }
        return true;
    }

    public static void main(String[] args) {
        HandleString hds = new HandleString();
        int a = hds.stringArrayCompare(hds.sg1);
        System.out.println(a);

        int b = hds.stringArrayCompare(hds.sg2);
        System.out.println(b);

        int c = hds.stringArrayCompare(hds.sg3);
        System.out.println(c);
    }
}

十分佩服，正解！

淡淡道；