Edit distance using DP

EditDistance.java

public class Solution {

    private static final int MATCHED = 1, DELETED = 1, INSERTED = 1;

    public int minDistance(String word1, String word2) {
        if (word1.length() == 0) return word2.length() * INSERTED;
        if (word2.length() == 0) return word1.length() * DELETED;
        if (word1.equals(word2)) return 0; // not much used though
        
        final int rows = word1.length();
        final int cols = word2.length();
        final int[][] table = new int[rows + 1][cols + 1];
        
        for (int i=1; i<=cols; ++i) table[0][i] = i;
        for (int i=1; i<=rows; ++i) table[i][0] = i;
        
        for (int i=1; i<=rows; ++i) {
            for (int j=1; j<=cols; ++j) {
                final int matched;
                if (word1.charAt(i-1) == word2.charAt(j-1)) {
                    matched = table[i-1][j-1];
                } else {
                    matched = table[i-1][j-1] + MATCHED;
                }
                final int delete = table[i-1][j] + DELETED;
                final int insert = table[i][j-1] + INSERTED;
                table[i][j] = Math.min(matched, Math.min(delete, insert));
            }
        }
        
        return table[rows][cols];
    }
}