LeetCode75——Day26

文章目录

一、题目

394. Decode String

Given an encoded string, return its decoded string.

The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. Note that k is guaranteed to be a positive integer.

You may assume that the input string is always valid; there are no extra white spaces, square brackets are well-formed, etc. Furthermore, you may assume that the original data does not contain any digits and that digits are only for those repeat numbers, k. For example, there will not be input like 3a or 2[4].

The test cases are generated so that the length of the output will never exceed 105.

Example 1:

Input: s = "3[a]2[bc]"

Output: "aaabcbc"

Example 2:

Input: s = "3[a2[c]]"

Output: "accaccacc"

Example 3:

Input: s = "2[abc]3[cd]ef"

Output: "abcabccdcdcdef"

Constraints:

1 <= s.length <= 30

s consists of lowercase English letters, digits, and square brackets '[]'.

s is guaranteed to be a valid input.

All the integers in s are in the range [1, 300].

二、题解

cpp 复制代码
class Solution {
public:
    string decodeString(string s) {
        string ans;
        stack<pair<int, int>> stk;
        int count = 0;
        for (auto x : s) {
            if (isdigit(x)) 
                count = 10 * count + (x - '0');
            else if (x == '[') {
                stk.push({count, ans.size()});
                count = 0;
            }
            else if (isalpha(x)) 
                ans += x;
            else if (x == ']') {
                int n = stk.top().first;
                string str = ans.substr(stk.top().second, ans.size() - stk.top().second);
                for (int i = 0; i < n - 1; i++) {
                    ans += str;
                }
                stk.pop();
            }
        }
        return ans;
    }
}; 
相关推荐
暴风鱼划水13 分钟前
三维重建【0-D】3D Gaussian Splatting:相机标定原理与步骤
算法·3d
陌路2035 分钟前
C23构造函数与析构函数
开发语言·c++
_OP_CHEN1 小时前
C++进阶:(二)多态的深度解析
开发语言·c++·多态·抽象类·虚函数·多态的底层原理·多态面试题
l1t1 小时前
利用DeepSeek修改数据结构提升求解集合程序效率
数据结构·python·deepseek
mount_myj2 小时前
敏感信息屏蔽(一)【java】
java·算法·极课堂
金色熊族3 小时前
装饰器模式(c++版)
开发语言·c++·设计模式·装饰器模式
先做个垃圾出来………3 小时前
偏移量解释
数据结构·算法
Dream it possible!3 小时前
LeetCode 面试经典 150_链表_旋转链表(64_61_C++_中等)
c++·leetcode·链表·面试
FanXing_zl3 小时前
基于整数MCU的FOC控制定标策略深度解析
单片机·嵌入式硬件·mcu·算法·定点运算·q15
立志成为大牛的小牛3 小时前
数据结构——三十三、Dijkstra算法(王道408)
数据结构·笔记·学习·考研·算法·图论