LeetCode - 1190. Reverse Substrings Between Each Pair of Parentheses

LeetCode - 1190. Reverse Substrings Between Each Pair of Parentheses

You are given a string s that consists of lower case English letters
and brackets.

Reverse the strings in each pair of matching parentheses, starting
from the innermost one.

Your result should not contain any brackets.

Input: s = “(abcd)”
Output: “dcba” Example 2:

Input: s = “(u(love)i)”
Output: “iloveu”

Input: s = “(ed(et(oc))el)”
Output: “leetcode”

Input: s = “a(bcdefghijkl(mno)p)q”
Output: “apmnolkjihgfedcbq”

  就是从最里边的括号开始，一对儿括号中的字符串翻转一次。有左右括号的题，一般都用 stack，这道题也可以用。每次读到一个左括号，记录目前的字符串的长度，也就是左括号在整个字符串中的位置，下一次读到右括号，直接翻转这区间内的字符串即可。

string reverseParentheses(string s) {
     
    stack<int> st;
    string res;
    for(const char& c : s){
     
        if(c == '(')
            st.push(res.length());
        else if(c == ')'){
     
            const int t = st.top();
            st.pop();
            reverse(res.begin() + t, res.end());
        }
        else
            res += c;
    }
    return res;
}