From f6359ab7ab5615649091dc41a7f72f414a6e5da8 Mon Sep 17 00:00:00 2001
From: chayan das <110921638+Chayandas07@users.noreply.github.com>
Date: Sat, 24 Aug 2024 17:39:27 +0530
Subject: [PATCH] Create 564. Find the Closest Palindrome

---
 564. Find the Closest Palindrome | 39 ++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 564. Find the Closest Palindrome

diff --git a/564. Find the Closest Palindrome b/564. Find the Closest Palindrome
new file mode 100644
index 0000000..001ab3a
--- /dev/null
+++ b/564. Find the Closest Palindrome	
@@ -0,0 +1,39 @@
+class Solution {
+public:
+    string nearestPalindromic(string n) {
+        if(n.length()==1)
+            return to_string(stoi(n)-1);
+        
+        int d = n.length();
+        vector<long> candidates;
+        candidates.push_back(pow(10,d-1)-1);
+        candidates.push_back(pow(10,d)+1);
+
+        int mid = (d+1)/2;
+        long prefix = stol(n.substr(0,mid));
+        vector<long> v = {prefix,prefix+1, prefix-1};
+        for(long i : v)
+        {
+            string postfix = to_string(i);
+            if(d%2!=0)
+                postfix.pop_back();
+            reverse(postfix.begin(), postfix.end());
+            string c = to_string(i)+postfix;
+            candidates.push_back(stol(c));
+        }
+        long mindiff = LONG_MAX;
+        long result;
+        long num = stol(n);
+        for(int i=0;i<5;i++)
+        {
+            if(candidates[i]!=num && abs(candidates[i]-num)<mindiff)
+            {
+                mindiff = abs(candidates[i]-num);
+                result = candidates[i];
+            }
+            else if(abs(candidates[i]-num)==mindiff)
+                result = min(result, candidates[i]);
+        }
+        return to_string(result);
+    }
+};