Create 0446-arithmetic-slices-ii-subsequence.java

Author: sujal-goswami

java/0446-arithmetic-slices-ii-subsequence.java

@@ -0,0 +1,21 @@
+public class Solution {
+    public int numberOfArithmeticSlices(int[] nums) {
+        int res = 0;
+        int n = nums.length;
+
+        Map<Long, Integer>[] dp = new HashMap[n];
+        for (int i = 0; i < n; i++) {
+            dp[i] = new HashMap<>();
+        }
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < i; j++) {
+                long diff = (long) nums[i] - (long) nums[j];
+                dp[i].put(diff, dp[i].getOrDefault(diff, 0) + 1 + dp[j].getOrDefault(diff, 0));
+                res += dp[j].getOrDefault(diff, 0);
+            }
+        }
+
+        return res;
+    }
+}