use std::collections::hash_map::Entry;
use std::collections::HashMap;

struct Solution {}

impl Solution {
    pub fn find_max_length(nums: Vec<i32>) -> i32 {
        let mut m = HashMap::new();
        let mut sum = 0;
        let mut max = 0;
        m.insert(0, -1); //初始和就是0,下标为-1,这样就算是有多个0也不会记错
        for i in nums.iter().enumerate() {
            if *i.1 == 0 {
                sum += -1;
            } else {
                sum += 1;
            }
            match m.entry(sum) {
                Entry::Occupied(e) => {
                    if i.0 as i32 - *e.get() > max {
                        max = i.0 as i32 - *e.get();
                    }
                }
                Entry::Vacant(mut e) => {
                    e.insert(i.0 as i32);
                }
            };
        }
        max as i32
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::share;
    #[test]
    fn test_reverse_list() {
        let t = Solution::find_max_length(vec![1, 1, 1, 0, 1, 1, 1, 0, 1]);
        assert_eq!(t, 2);
    }
}