java day20训练 ①最长公共子串长度(动态规划)②字符串反转(双指针迭代)

目录

①公共子串计算

 ②字符串反转

①公共子串计算

import java.util.*;
public class Main{
    public static int func(String str1,String str2){
        char[]arr1=str1.toCharArray();
        char[]arr2=str2.toCharArray();
        int len1=str1.length();
        int len2=str2.length();
        //定义最长字符串长度
        int maxlen=0;
        int[][]arr=new int[len1+1][len2+1];
        for(int i=1;i<=len1;i++){
            for(int j=1;j<=len2;j++){
            if(arr1[i-1]==arr2[j-1]){
                arr[i][j]=arr[i-1][j-1]+1;
            }
                if(maxlen=s2.length()){
                int a=func(s1,s2);
                System.out.println(a);
            }
            if(s1.length() 
 ②字符串反转 
 
import java.util.*;
public class Main{
    //双指针迭代
    public static void main(String[]args){
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
            String s=sc.nextLine();
            char[]arr=s.toCharArray();
            int start=0;
            int end=arr.length-1;
            while(start