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Longest Common Subsequence

medium
Acceptance: 51%
Dynamic Programming

Given two strings, determine the length of their longest common subsequence. A subsequence preserves relative order but need not consist of consecutive characters. Return 0 if no common subsequence exists.

Examples

Example 1:
Input:text1 = "mango", text2 = "magnolia"
Output:4
Explanation: "mago" is a common subsequence of length 4.
Example 2:
Input:text1 = "xyz", text2 = "abc"
Output:0
Explanation: The two strings share no characters.

Hints

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class Solution {
    public int longestCommonSubsequence(String text1, String text2) {
        int m = text1.length(), n = text2.length();
        int[][] dp = new int[m + 1][n + 1];
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if (text1.charAt(i - 1) == text2.charAt(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[m][n];
    }
}
Time complexityO(m * n)
Space complexityO(m * n)