package top.qaqaq.java.P477;

import org.junit.jupiter.api.Test;

import java.util.Arrays;

/**
 * @author RichieZhang
 * @create 2022-10-23 下午 3:24
 */
public class StringDemo2 {

    /*
    获取两个字符串中最大相同子串。比如：
    str1 = "abcwerthelloyuiodef“;str2 = "cvhellobnm"
    提示：将短的那个串进行长度依次递减的子串与较长的串比较。

     */
    //前提：两个字符串中只有一个最大相同字串
    public String getMaxSameString(String str1, String str2) {
        if (str1 != null && str2 != null) {
            String maxStr = (str1.length() >= str2.length()) ? str1 : str2;
            String minStr = (str1.length() < str2.length()) ? str1 : str2;
            int length = minStr.length();
            for (int i = 0; i < length; i++) {

                for (int x = 0, y = length - i; y <= length; x++, y++) {
                    String subStr = minStr.substring(x, y);
                    if (maxStr.contains(subStr)) {
                        return subStr;
                    }
                }
            }

        }
        return null;
    }

    // 如果存在多个长度相同的最大相同子串
    // 此时先返回String[]，后面可以用集合中的ArrayList替换，较方便
    public String[] getMaxSameString1(String str1, String str2) {
        if (str1 != null && str2 != null) {
            StringBuffer sBuffer = new StringBuffer();
            String maxString = (str1.length() > str2.length()) ? str1 : str2;
            String minString = (str1.length() > str2.length()) ? str2 : str1;

            int len = minString.length();
            for (int i = 0; i < len; i++) {
                for (int x = 0, y = len - i; y <= len; x++, y++) {
                    String subString = minString.substring(x, y);
                    if (maxString.contains(subString)) {
                        sBuffer.append(subString + ",");
                    }
                }
//                System.out.println(sBuffer);
                if (sBuffer.length() != 0) {
                    break;
                }
            }
            String[] split = sBuffer.toString().replaceAll(",$", "").split("\\,");
            return split;
        }

        return null;
    }

    @Test
    public void testGetMaxSameString(){
        String str1 = "abcwerthello1yuiodefabcdef";
        String str2 = "cvhello1bnmabcdef";
        String[] maxSameStrings = getMaxSameString1(str1, str2);
        System.out.println(Arrays.toString(maxSameStrings));
    }
}