edit 564

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_564.java

@@ -21,7 +21,48 @@
 public class _564 {
 
     public String nearestPalindromic(String n) {
-        return "";
+        if (n.length() >= 2 && allNine(n)) {
+            String s = "1";
+            for (int i = 0; i < n.length() - 1; i++) {
+                s += "0";
+            }
+            s += "1";
+            return s;
+        }
+        boolean isOdd = (n.length() % 2 != 0);
+        String left = n.substring(0, (n.length() + 1) / 2);
+        long[] increment = {-1, 0, +1};
+        String ret = n;
+        long minDiff = Long.MAX_VALUE;
+        for (long i : increment) {
+            String s = getPalindrom(Long.toString(Long.parseLong(left) + i), isOdd);
+            if (n.length() >= 2 && (s.length() != n.length() || Long.parseLong(s) == 0)) {
+                s = "";
+                for (int j = 0; j < n.length() - 1; j++) {
+                    s += "9";
+                }
+            }
+            long diff = s.equals(n) ? Long.MAX_VALUE : Math.abs(Long.parseLong(s) - Long.parseLong(n));
+            if (diff < minDiff) {
+                minDiff = diff;
+                ret = s;
+            }
+        }
+        return ret;
+    }
+
+    private String getPalindrom(String s, boolean isOdd) {
+        String right = new StringBuilder(s).reverse().toString();
+        return isOdd ? s.substring(0, s.length() - 1) + right : s + right;
+    }
+
+    private boolean allNine(String s) {
+        for (int i = 0; i < s.length(); i++) {
+            if (s.charAt(i) != '9') {
+                return false;
+            }
+        }
+        return true;
     }
 
 }