计算两个字符串编辑距离

public static int levenDistance(String s, String t) {
if (s == null || t == null) {
return 10;
}
s = s.toLowerCase();
t = t.toLowerCase();
/* if (Math.abs(s.length() - t.length()) >= 3) {
return 3;
}*/
int d[][]; // matrix
int n; // length of s
int m; // length of t
int i; // iterates through s
int j; // iterates through t
char s_i; // ith character of s
char t_j; // jth character of t
int cost; // cost

// Step 1
n = s.length();
m = t.length();
if (n == 0) {
return m;
}
if (m == 0) {
return n;
}
d = new int[n + 1][m + 1];

// Step 2
for (i = 0; i <= n; i++) {
d[i][0] = i;
}

for (j = 0; j <= m; j++) {
d[0][j] = j;
}

// Step 3
for (i = 1; i <= n; i++) {

s_i = s.charAt(i - 1);

// Step 4
for (j = 1; j <= m; j++) {

t_j = t.charAt(j - 1);

// Step 5
if (s_i == t_j) {
cost = 0;
} else {
cost = 1;
}

// Step 6
// d[i][j] = Minimum(d[i - 1][j] + 1, d[i][j - 1] + 1,
// d[i - 1][j - 1] + cost);
// 求三个数的最小值(a<b?a:b)<c?(a<b?a:b):c
d[i][j] = ((d[i - 1][j] + 1) < (d[i][j - 1] + 1) ? (d[i - 1][j] + 1)
: (d[i][j - 1] + 1)) < (d[i - 1][j - 1] + cost) ? ((d[i - 1][j] + 1) < (d[i][j - 1] + 1) ? (d[i - 1][j] + 1)
: (d[i][j - 1] + 1))
: (d[i - 1][j - 1] + cost);

}

}

// Step 7
return d
[m];

}