Create 400. Nth Digit.java

Author: futurus

400. Nth Digit.java

@@ -0,0 +1,32 @@
+// Brute (Memory Limit)
+public class Solution {
+    public int findNthDigit(int n) {
+        StringBuilder sb = new StringBuilder();
+        
+        for (int i = 1; ; i++) {
+            sb.append(i);
+            
+            if (sb.length() >= n) {
+                return sb.charAt(n-1) - '0';
+            }
+        }
+    }
+}
+
+// Space improvement (Time Limit)
+public class Solution {
+    public int findNthDigit(int n) {
+        StringBuilder sb = new StringBuilder();
+        
+        for (int i = 1; ; i++) {
+            sb.append(i);
+            
+            if (n > sb.length()) {
+                n -= sb.length();
+                sb.delete(0, sb.length());
+            } else {
+                return sb.charAt(n-1) - '0';
+            }
+        }
+    }
+}