腾讯后台------压缩算法

 string类型，包含很多库函数，

#include <iostream>
#include <string>
using namespace std;

int main() {
    string s;
    cin >> s;
    int i = 0;
    while (i < s.length()) 
    {
        if (s[i] == ']') 
        {
            int j = i;//j用来向前寻找与]相匹配的[
            int k = 0;//k用来记录'|'所在位置
            while (s[j] != '[') 
            {
                if (s[j] == '|')
                    k = j;
                j--;
            }
            int len = stoi(s.substr(j + 1, k - j-1));
            string s1 = s.substr(k + 1, i - k - 1);
            string s2;
            for (int si = 0; si < len; si++) 
            {//将识别到的括号内容进行解码
                s2 += s1;
            }
            s = s.replace(j, i - j + 1, s2);
            i = j;//替换后i所指向的内容变化，从替换部分的头开始再寻找
        }
        i++;
    }
    cout << s << endl;
}

下面代码通过30%case，，，to_string函数一般将int转化成string型，  会将char转换成ASIIC码 “AB”   转成 "6566"

#include<iostream>
#include<stack>
#include<string>
#include<algorithm>
using namespace std;
int main()
{
    
    string str;
    while (cin >> str)
    {
        //cout << str << endl;
        stack<string>record;
        for (int i = 0; i < str.size(); i++)
        {
            if ((str[i] >= 'A' && str[i] <= 'Z') || (str[i] >= '0' && str[i] <= '9') || str[i] == '|' || str[i] == '[')
            {
                //cout << str[i] << endl;
                string tmp;
                tmp.push_back(str[i]);
                record.push(tmp);
            }
            else if (str[i] == ']')
            {
                string str_1 = "";
                while (record.top() != "|")
                {
                    str_1 += record.top();
                    record.pop();
                }
                record.pop();
                string str_2 = "";
                while (record.top() != "[")
                {
                    str_2 += record.top();
                    record.pop();
                }
                record.pop();
                int n = atoi(str_2.c_str());
                for (int i = 0; i < n; i++)
                {
                    record.push(str_1);
                }
            }
        }
        string res="";
        while (record.empty() == false)
        {
            //cout << record.top() << endl;
            res += record.top();
            record.pop();
        }
        //cout << res << endl;
        reverse(res.begin(), res.end());
        //cout << "1" << endl;
        cout << res << endl;
    }
}