Given two strings text1 and text2, return the length of their longest common subsequence.

A subsequence of a string is a new string generated from the original string with some characters(can be none) deleted without changing the relative order of the remaining characters. (eg, "ace" is a subsequence of "abcde" while "aec" is not). A common subsequence of two strings is a subsequence that is common to both strings.

If there is no common subsequence, return 0.

Example 1:

Input: text1 = "abcde", text2 = "ace" 
Output: 3  
Explanation: The longest common subsequence is "ace" and its length is 3.


Example 2:

Input: text1 = "abc", text2 = "abc"
Output: 3
Explanation: The longest common subsequence is "abc" and its length is 3.



Example 3:

Input: text1 = "abc", text2 = "def"
Output: 0
Explanation: There is no such common subsequence, so the result is 0.

Solution:

func longestCommonSubsequence(text1 string, text2 string) int {
    len1 := len(text1)
    len2 := len(text2)
    
    //init dp
    dp := make([][]int, len1+1)
    for i := 0; i <= len1; i++ {
        dp[i] = make([]int, len2+1)
    }
    
    for i := 1; i <=len1; i++ {
        for j:= 1; j <=len2; j++ {
            dp[i][j] = max(dp[i-1][j], dp[i][j-1])
            if text1[i-1] == text2[j-1] {
                dp[i][j] = max(dp[i][j], dp[i-1][j-1] + 1)
            }
        }
    }
    
    return dp[len1][len2]
}
func max(a, b int) int {
    if a > b {
        return a
    }
    return b
}