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/** | |
* @param {string} n | |
* @return {string} | |
*/ | |
var nearestPalindromic = function(n) { | |
const nN = BigInt(n); | |
if (n == 11n) { | |
return "9"; | |
} | |
const palindrome = getUniquePalindrome(n); | |
if (palindrome <= 0) { | |
return palindrome.toString(); | |
} | |
const nPalindrome = BigInt(palindrome); | |
const res = [ palindrome ]; | |
const cnt = (n + '').length; | |
for (let i = 0; i < cnt; i++) { | |
res.push(getPalindrome(nN + BigInt(Math.pow(10, i)))); | |
res.push(getPalindrome(nN - BigInt(Math.pow(10, i)))); | |
} | |
// console.log(res); | |
return res.reduce((acc, cur) => | |
cur != n && | |
( | |
Math.abs(Number(cur - nN)) < Math.abs(Number(acc - nN)) || | |
(cur < acc && Math.abs(Number(cur - nN)) == Math.abs(Number(acc - nN))) | |
) ? cur : acc, 0n).toString(); | |
}; | |
const getPalindrome = n => { | |
const digits = ('' + n).split(''); | |
for(let i = 0, len = digits.length, mid = (len / 2); i < mid; i++) { | |
digits[len-i-1] = digits[i]; | |
} | |
return BigInt(digits.join('')); | |
}; | |
const getUniquePalindrome = n => { | |
let result = getPalindrome(n); | |
if (result != n) { | |
return result; | |
} | |
// console.log(result, n, result[Math.ceil(result.length / 2) - 1]); | |
result = ('' + result).split(''); | |
if (result[Math.ceil(result.length / 2) - 1] > 1) { | |
result[Math.ceil(result.length / 2) - 1] = Number(result[Math.ceil(result.length / 2) - 1]) - 1; | |
} else { | |
result[Math.ceil(result.length / 2) - 1] = Number(result[Math.ceil(result.length / 2) - 1]) + 1; | |
} | |
console.log(result); | |
return getPalindrome(result.join('')); | |
}; |
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