In practice, this distance can be used as the insertion key in a BK-tree used for auto-complete or spell checking, ie it is used in my JComplete project.
The dynamic programming approach in Java:
private int levenshtein(String string1, String string2) {
int maxi = string1.length() + 1;
int maxj = string2.length() + 1;
int[][] distance = new int[maxi][maxj];
for (int i = 1; i < maxi; i++) {
distance[i][0] = i;
}
for (int j = 1; j < maxj; j++) {
distance[0][j] = j;
}
for (int j = 1; j < maxj; j++) {
for (int i = 1; i < maxi; i++) {
if (string1.charAt(i - 1) == string2.charAt(j - 1)) {
distance[i][j] = distance[i - 1][j - 1];
} else {
distance[i][j] = min(distance[i - 1][j] + 1,
distance[i][j - 1] + 1,
distance[i - 1][j - 1] + 1
);
}
}
}
return distance[maxi - 1][maxj - 1];
}
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