refactor: match JS solution 1143 with video explaination

abstrekt · abstrekt · commit 594a76ec54cb · 2022-07-13T00:02:49.000+05:30
diff --git a/javascript/1143-Longest-Common-Subsequence.js b/javascript/1143-Longest-Common-Subsequence.js
@@ -1,17 +1,16 @@
 var longestCommonSubsequence = function (text1, text2) {
-  let m = text1.length;
-  let n = text2.length;
+  let m = text1.length,
+    n = text2.length,
+    DP = new Array(m + 1).fill(0).map(_ => new Array(n + 1).fill(0));
 
-  let table = new Array(m + 1).fill().map(() => new Array(n + 1).fill(0));
-
-  for (let i = 1; i <= m; i++) {
-    for (let j = 1; j <= n; j++) {
-      if (text1.charAt(i - 1) !== text2.charAt(j - 1)) {
-        table[i][j] = Math.max(table[i - 1][j], table[i][j - 1]);
+  for (let x = m - 1; x >= 0; x--)
+    for (let y = n - 1; y >= 0; y--) {
+      if (text1[x] === text2[y]) {
+        DP[x][y] = 1 + DP[x + 1][y + 1];
       } else {
-        table[i][j] = table[i - 1][j - 1] + 1;
+        DP[x][y] = Math.max(DP[x + 1][y], DP[x][y + 1]);
       }
     }
-  }
-  return table[m][n];
-};
+
+  return DP[0][0];
+};
