1143. Longest Common Subsequence
Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.
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.
For example, "ace" is a subsequence of "abcde". A common subsequence of two strings is a subsequence that is common to both strings.
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.
Constraints:
- 1 <= text1.length, text2.length <= 1000
- text1 and text2 consist of only lowercase English characters.
class Solution {
public int longestCommonSubsequence(String text1, String text2) {
int a = text1.length();
int b = text2.length();
int[][] dp = new int[a+1][b+1];
for(int i=1;i<=a;i++){
for(int j=1;j<=b;j++){
char c1 = text1.charAt(i - 1);
char c2 = text2.charAt(j - 1);
if(c1==c2){
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[a][b];
}
}