Create Longest Arithmetic Subsequence.java

varunu28 · web-flow · commit dd8dd6550cf7 · 2022-07-07T10:51:25.000-07:00
diff --git a/Medium/Longest Arithmetic Subsequence.java b/Medium/Longest Arithmetic Subsequence.java
@@ -0,0 +1,15 @@
+class Solution {
+  public int longestArithSeqLength(int[] nums) {
+    int result = 2;
+    Map<Integer, Integer>[] dp = new HashMap[nums.length];
+    for (int i = 0; i < nums.length; i++) {
+      dp[i] = new HashMap<>();
+      for (int j = 0; j < i; j++) {
+        int diff = nums[i] - nums[j];
+        dp[i].put(diff, dp[j].getOrDefault(diff, 1) + 1);
+        result = Math.max(result, dp[i].get(diff));
+      }
+    }
+    return result;
+  }
+}
