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challenge_45.js
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68 lines (64 loc) · 1.47 KB
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function isPallindrome(n) {
var digits = ""
, digits_len = 0
, half_digits = 0
, i = 0
;
if (typeof(n) !== 'number') {
return false;
}
digits = n.toString().split("");
if (digits[0] === '-') {
digits.shift();
}
digits_len = digits.length;
if ( digits_len === 0 ) {
return false;
} else if ( digits_len === 1) {
return true;
} else if (digits_len === 2 ) {
return digits[0] === digits[1];
} else {
half_digits = Math.floor(digits_len/2);
do {
if (digits[i] !== digits[ digits_len - i - 1 ]) {
return false;
}
i += 1;
} while( i < half_digits ) ;
}
return true;
}
function reverseNumber(n) {
var rn = n.toString(10).split('').reverse();
if (rn[rn.length-1] === '-') {
rn.pop();
rn.unshift('-');
}
return parseInt(rn.join(''));
}
function driver(n) {
var rs = n // running sum
, i = 0 // iteration counter
, p_flag = false // pallidrome found flag
;
do {
if (i >= 10000) {break;}
rs += reverseNumber(rs);
i += 1;
p_flag = isPallindrome(rs);
//console.log('driver: p_flag => ' + p_flag + " | rs: " + rs);
} while ( p_flag !== true);
if (p_flag !== true ) {
return [i];
} else {
return [i,rs];
}
}
var fs = require("fs"), z;
fs.readFileSync(process.argv[2]).toString().split('\n').forEach(function (line) {
if (line !== "") { // ignore empty lines
z = driver( parseInt(line) );
console.log( z.join(" ") );
}
});