1320. Minimum Distance to Type a Word Using Two Fingers

leetcode1320.swift

class Solution {
    func minimumDistance(_ word: String) -> Int {
        
        let array = Array(word).compactMap{ $0.asciiValue }.map{ Int($0 - 65) }
        
        var dp = [[Int]](repeating:[Int](repeating:Int.max/2, count:27), count:word.count + 1)
        
        dp[0][26] = 0
        
        
        for i in 1...word.count {
            let current = array[i-1]
            let previous = (i == 1) ? 26 : array[i-2]

            for c in 0...26 {
                dp[i][c] = min(dp[i][c],dp[i-1][c] + distance(previous,current)) // move previous, another stay in c
                dp[i][previous] = min(dp[i][previous],dp[i-1][c] + distance(c,current)) // move c, another stay in previous
            }
            
        }
        
        return dp[word.count].min()!
    }

    func distance(_ a:Int, _ b:Int) -> Int {
        if a == 26 {
            return 0
        }
        
        return abs(a/6 - b/6) + abs(a%6 - b%6)
    }
}