add KthNumber solution

Author: jakovmitrovski

medium300/KthNumber.java

@@ -0,0 +1,29 @@
+package medium300;
+
+public class KthNumber {
+
+    public String kthNumber(int[] primes, int k) {
+
+        long[] dp = new long[k + 1];
+        dp[1] = 1;
+
+        for (int x = 2; x <= k; x++) {
+            long ans = Long.MAX_VALUE;
+            for (int y = 1; y < x; y++) {
+                for (int i = 0; i < primes.length; i++) {
+                    long nval = dp[y] * primes[i];
+                    if (nval > dp[x - 1])
+                        ans = Math.min(nval, ans);
+                }
+                dp[x] = ans;
+            }
+        }
+
+        return String.valueOf(dp[k]);
+    }
+
+    public static void main(String[] args) {
+        KthNumber k = new KthNumber();
+        System.out.println(k.kthNumber(new int[] { 2, 3 }, 1000));
+    }
+}