1021. Remove Outermost Parentheses
A valid parentheses string is either empty ("")
, "(" + A + ")"
, or A + B
, where A
and B
are valid parentheses strings, and +
represents string concatenation. For example, ""
, "()"
, "(())()"
, and "(()(()))"
are all valid parentheses strings.
A valid parentheses string S
is primitive if it is nonempty, and there does not exist a way to split it into S = A+B
, with A
and B
nonempty valid parentheses strings.
Given a valid parentheses string S
, consider its primitive decomposition: S = P_1 + P_2 + ... + P_k
, where P_i
are primitive valid parentheses strings.
Return S
after removing the outermost parentheses of every primitive string in the primitive decomposition of S
.
Example 1:
Input: "(()())(())" Output: "()()()" Explanation: The input string is "(()())(())", with primitive decomposition "(()())" + "(())". After removing outer parentheses of each part, this is "()()" + "()" = "()()()".
Example 2:
Input: "(()())(())(()(()))" Output: "()()()()(())" Explanation: The input string is "(()())(())(()(()))", with primitive decomposition "(()())" + "(())" + "(()(()))". After removing outer parentheses of each part, this is "()()" + "()" + "()(())" = "()()()()(())".
Example 3:
Input: "()()" Output: "" Explanation: The input string is "()()", with primitive decomposition "()" + "()". After removing outer parentheses of each part, this is "" + "" = "".
Note:
S.length <= 10000
S[i]
is"("
or")"
S
is a valid parentheses string
Rust Solution
struct Solution;
impl Solution {
fn remove_outer_parentheses(s: String) -> String {
let mut res: String = "".to_string();
let mut count = 0;
for c in s.chars() {
if c == '(' {
count += 1;
if count > 1 {
res.push(c);
}
} else {
count -= 1;
if count != 0 {
res.push(c);
}
}
}
res
}
}
#[test]
fn test() {
let s = "(()())(())".to_string();
let t = "()()()".to_string();
assert_eq!(Solution::remove_outer_parentheses(s), t);
let s = "(()())(())(()(()))".to_string();
let t = "()()()()(())".to_string();
assert_eq!(Solution::remove_outer_parentheses(s), t);
let s = "()()".to_string();
let t = "".to_string();
assert_eq!(Solution::remove_outer_parentheses(s), t);
}
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