[刷题]Longest Common Subsequence

[LintCode]Longest Common Subsequence

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) {        // 2015-05-19 O(n^2)        if (A == null || B == null || A.length() == 0 || B.length() == 0) {            return 0;        }        int m = A.length();        int n = B.length();        int[][] lcs = new int[m + 1][n + 1]; // (m + 1) * (n + 1)        for (int i = 0; i <= m; i++) {            lcs[i][0] = 0;        }        for (int j = 1; j <= n; j++) {            lcs[0][j] = 0;        }                for (int i = 1; i <= m; i++) {            for (int j = 1; j <= n; j++) {                if (A.charAt(i - 1) == B.charAt(j - 1)) {                    lcs[i][j] = lcs[i - 1][j - 1] + 1;                } else {                    lcs[i][j] = Math.max(lcs[i - 1][j], lcs[i][j - 1]);                }            }        }        return lcs[m][n];    }}