Med Given two strings, find the longest common subsequence (LCS).
Your code should return the length of LCS.
Thoughts
它是edit distance的变种，只是min换乘了max,注意和lc substr的区分。
Code
public class Solution {
/**
* @param A, B: Two strings.
* @return: The length of longest common subsequence of A and B.
*/
public int longestCommonSubsequence(String A, String B) {
int m = A.length();
int n = B.length();
if (m == 0 || n == 0) {
return 0;
}
// f: A前i, 与B的前j个字符相匹配的LCS
int[][] f = new int[m + 1][n + 1];
// loop
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= n; j++) {
f[i][j] = Math.max(f[i - 1][j], f[i][j - 1]);
int edit = f[i - 1][j - 1];
if (A.charAt(i - 1) == B.charAt(j - 1)) {
edit++;
}
f[i][j] = Math.max(edit, f[i][j]);
}
}
return f[m][n];
}
}