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1545-find-kth-bit-in-nth-binary-string/1545-find-kth-bit-in-nth-binary-string.java

@@ -0,0 +1,20 @@
+class Solution {
+    StringBuilder ans = new StringBuilder("0");
+    private StringBuilder invertAndReverse(StringBuilder sb) {
+        StringBuilder temp = new StringBuilder();
+        for (int i = 0; i < sb.length(); i++) {
+            char curr = sb.charAt(i);
+            if (curr == '0') temp.append("1");
+            else temp.append("0");
+        }
+        return temp.reverse();
+    }
+
+    public char findKthBit(int n, int k) {
+        if (ans.length() >= k) return ans.charAt(k - 1);
+        if (n <= 1) return ans.charAt(k - 1);
+        StringBuilder temp = invertAndReverse(ans);
+        ans.append("1").append(temp);
+        return findKthBit(n - 1, k);
+    }
+}