1143. 最长公共子序列（双序列型动态规划）

class Solution {
    public int longestCommonSubsequence(String text1, String text2) {
         char[] arr1 = text1.toCharArray();
        char[] arr2 = text2.toCharArray();
        //dp[i][j]代表arr1的前i个字符和arr2的前j个字符的最长公共子序列长度
        int[][] dp = new int[arr1.length + 1][arr2.length + 1];
        for (int i = 1; i <= arr1.length; i++) {
            for (int j = 1; j <= arr2.length; j++) {
                if (arr1[i-1] == arr2[j-1]) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                } else {
                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
                } 
            }
        }
        return dp[arr1.length][arr2.length];
    }
}