Merge pull request neetcode-gh#2652 from ColstonBod-oy/patch-11

Update 1143-longest-common-subsequence.java

java/1143-longest-common-subsequence.java

@@ -22,33 +22,20 @@ public int LCS(String s1, String s2, int i, int j, int[][] dp) {
 
 // Iterative version
 class Solution {
-
+ 
  public int longestCommonSubsequence(String text1, String text2) {
- //O(n*m)/O(n*m) time/memory
- if (text1.isEmpty() || text2.isEmpty()) {
- return 0;
- }
-
- int[][] dp = new int[text1.length() + 1][text2.length() + 1];
-
- for (int i = 0; i <= text1.length(); i++) {
- dp[i][0] = 0;
- }
-
- for (int j = 0; j <= text2.length(); j++) {
- dp[0][j] = 0;
- }
+ int[][] dp = new int[text1.length() + 1][text2.length() + 1]; 
 
- for (int i = 1; i <= text1.length(); i++) {
- for (int j = 1; j <= text2.length(); j++) {
- if (text1.charAt(i - 1) == text2.charAt(j - 1)) {
- dp[i][j] = 1 + dp[i - 1][j - 1];
+ for (int i = text1.length() - 1; i >= 0; i--) {
+ for (int j = text2.length() - 1; j >= 0; j--) {
+ if (text1.charAt(i) == text2.charAt(j)) {
+ dp[i][j] = 1 + dp[i + 1][j + 1];
  } else {
- dp[i][j] = Math.max(dp[i][j - 1], dp[i - 1][j]);
+ dp[i][j] = Math.max(dp[i][j + 1], dp[i + 1][j]);
  }
  }
  }
 
- return dp[text1.length()][text2.length()];
+ return dp[0][0];
  }
 }