一、题目描述

二、算法原理

三、代码实现

class Solution {
public:string decodeString(string s) {stack<string> s1;s1.push("");stack<int> s2;int i = 0, n = s.size();while (i < n){//1.如果是数字入数字栈if (s[i] >= '0' && s[i] <= '9'){int sum = 0;while (s[i] >= '0' && s[i] <= '9'){int val = s[i] - '0';sum = sum * 10 + val;i++;}s2.push(sum);}//2.如果是[ 统计后面的字符串入字符串栈else if (s[i] == '['){string str;i++;while (s[i] >= 'a' && s[i] <= 'z') str += s[i++];s1.push(str);}//3.如果是] 解码后入字符栈顶的子串后面else if (s[i] == ']'){int times = s2.top();s2.pop();string temp = s1.top();s1.pop();while (times--) s1.top() += temp;i++;}//4.如果是字符 把字符串入栈顶的子串后面else if (s[i] >= 'a' && s[i] <= 'z'){string str;while (s[i] >= 'a' && s[i] <= 'z') str += s[i++];if (str.size() > 0) s1.top() += str;}}return s1.top();}
};