19--longest-common-subsequence.java

class Solution {
    public int longestCommonSubsequence(String text1, String text2) {
        int[][] dp = new int[text1.length() + 1][text2.length() + 1];
        for (int i = 1; i < dp.length; i++) {
            for (int j = 1; j < dp[0].length; j++) {
                if (text1.charAt(i - 1) == text2.charAt(j - 1)) {
                    dp[i][j] = 1 + dp[i-1][j-1];
                } else {
                    dp[i][j] = Math.max(dp[i][j-1], dp[i-1][j]);
                }
            }
        }
        return dp[text1.length()][text2.length()];
    }
} // TC: O(m * n), SC: O(m * n)