题解 | #压缩算法#

记录区间的下标
删除该区间 并替换成 该区间对应的字符串

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param str string字符串
     * @return string字符串
     */
    public static String compress (String str) {
        if(!str.contains("[")){
            return str;
        }
        StringBuilder sb=new StringBuilder(str);
        // res 初始化 并将str赋值
        int len=str.length();
        char[] ch=str.toCharArray();
        Deque<Integer> stack=new LinkedList<>();
        for(int i=0;i<len;i++){
            if(ch[i]=='['){
                stack.push(i);//记录‘【’下标
            }else if(ch[i]==']'){
                int l=stack.pop();
                int r=i;
                String s=str.substring(l+1,r);
                String res=helper(s);
                sb.delete(l,r+1);
                sb.insert(l,res);
                break;
            }
        }
        return compress(sb.toString());
    }

    //拆分括号中的
    public static String helper(String str){
        StringBuilder sb=new StringBuilder();
        String[] d=str.split("\\|");
        int num=Integer.parseInt(d[0]);
        String s=d[1];
        for(int i=0;i<num;i++){
            sb.append(s);
        }
        return sb.toString();
    }
}

下面这个方法最后一个用例超时 过不去

package test;

import java.util.Scanner;
import java.util.*;
import java.io.*;


public class Main{
    public static void main(String[] args) {

        Scanner sc = new Scanner(new BufferedInputStream(System.in));

        String pass = sc.nextLine();
        Stack<Character> stack = new Stack<>();
        Stack<Integer> numstack = new Stack<>();
        StringBuffer res = new StringBuffer();

        String temp = "";
        for(int i=0;i<pass.length();i++){
            // 【 入栈
            if(pass.charAt(i) == '[')
            {   stack.push(pass.charAt(i));
                String num_c = "";
                while(pass.charAt(++i) != '|'){
                    num_c += pass.charAt(i);
                }
                numstack.push(Integer.valueOf(num_c));
            }
            // 】 处理栈内
            else if(pass.charAt(i) == ']'){
                int num = numstack.pop();
                String temp2 = "";
                while(!stack.empty() && stack.peek() != '['){
                    temp2 = stack.pop() + temp2 ;
                }
                stack.pop(); //弹出 【

                temp = "";
                if(stack.empty()){
                    for(int j=0;j<num;j++){
                        temp +=temp2;
                    }
                    for (int k=0;k<temp.length();k++){
                        stack.push(temp.charAt(k));
                    }

                    temp2 = "";
                    while(!stack.empty()){
                        temp2 = stack.pop() + temp2 ;
                    }
                    res.append(temp2);
                }
                else{
                    for(int j=0;j<num;j++){
                            temp +=temp2;
                        }
                    for (int k=0;k<temp.length();k++){
                        stack.push(temp.charAt(k));
                    }
                }
            }
            else if(stack.empty()){
                res.append(pass.charAt(i));
            }
            else if (!stack.empty()){
                stack.push(pass.charAt(i));
            }

        }
        System.out.println(res.toString());
    }

}