g0301_0400.s0394_decode_string.Solution.rs Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-all Show documentation

104 LeetCode algorithm problem solutions

There is a newer version: 1.8

// #Medium #Top_100_Liked_Questions #String #Stack #Recursion #Level_1_Day_14_Stack #Udemy_Strings
// #Big_O_Time_O(n)_Space_O(n) #2024_09_12_Time_0_ms_(100.00%)_Space_2.1_MB_(24.04%)

impl Solution {
    pub fn decode_string(s: String) -> String {
        s
        .chars()
        .fold((String::new(), String::new(), Vec::new()), |(mut next_string, mut next_integer, mut stack): (String, String, Vec<(usize, String)>), c| {
            match c {
                '0'..='9' => {
                    next_integer.push(c);
                    (next_string, next_integer, stack)
                },
                '[' => {
                    stack.push((next_integer.parse::().unwrap(), next_string));
                    next_integer.clear();
                    (String::new(), next_integer, stack)
                },
                ']' => {
                    let (last_integer, left_string) = stack.pop().unwrap();
                    let next_string = left_string + &next_string.repeat(last_integer);
                    (next_string, next_integer, stack)
                },
                c => {
                    next_string.push(c);
                    (next_string, next_integer, stack)
                }
            }
        }).0
    }
}