/**
 * [97] Interleaving String
 */
pub struct Solution {}

// submission codes start here

impl Solution {
    pub fn is_interleave(s1: String, s2: String, s3: String) -> bool {
        let (s1, s2, s3): (Vec<char>, Vec<char>, Vec<char>) = (
            s1.chars().collect(),
            s2.chars().collect(),
            s3.chars().collect(),
        );
        let (n, m, t) = (s1.len(), s2.len(), s3.len());

        if n + m != t {
            return false;
        }

        let mut dp = vec![false; m + 1];
        dp[0] = true;

        for i in 0..=n {
            for j in 0..=m {
                if i == 0 && j == 0 {
                    continue;
                }

                let p = i + j - 1;

                if i != 0 {
                    dp[j] &= s1[i - 1] == s3[p];
                }

                if j != 0 {
                    dp[j] |= dp[j - 1] && s2[j - 1] == s3[p];
                }
            }
        }

        dp[m]
    }
}

// submission codes end

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_97() {
        assert!(Solution::is_interleave(
            "aabcc".to_owned(),
            "dbbca".to_owned(),
            "aadbbcbcac".to_owned()
        ));
    }
}