Add Itrative version of Longest Common Subsequence

java/1143-Longest-Common-Subsequence.java

@@ -17,3 +17,39 @@ public int LCS(String s1, String s2, int i, int j, int[][] dp) {
  }
 
 }
+
+
+// Itrative 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;
+ }
+
+ 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];
+
+ } else {
+ dp[i][j] = Math.max(dp[i][j - 1], dp[i - 1][j]);
+ }
+
+ }
+ }
+
+ return dp[text1.length()][text2.length()];
+ }
+}
+