JS code for calculating the day of perfect symmetry in the world, rough version

JS code for calculating the day of perfect symmetry in the world, rough version_javascript skills

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Release： 2016-05-16 17:59:38

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For example, 20111102
I was bored in the afternoon and wrote one. The code was not optimized.
I just wrote it out of boredom.
If anyone is interested in optimizing the code, thank you very much

After calculation, from 2000 to 3000 AD, there are a total of 36 qualifying days of perfect symmetry in the world.
When you see some blogs in the garden, you can add "run" below to directly execute the Html code. I don't know how to fix it, can someone tell me

Copy Code The code is as follows:

Palindromes after 1000 AD
<script> /** * Change the date into a standard 8-bit format, such as 20111102 * Divide it into four segments: 20 11 11 02 for the century, year, month, and day * The time complexity of the year-by-year algorithm is O(n3), and the final result can be obtained from the last four digits, month and day, which is more efficient * Because the mantissa of February in leap years is 9, which exceeds the long history of mankind, so there is no need to consider */ ;;(function(){ var theDateList=[]; //The maximum value of the century when a palindrome day occurs var maxForCentury=30; //The minimum value of the century when a palindrome day occurs var minForCentury=20; //The maximum value of the number of years when a palindrome day may occur, only rough processing is done here var maxForYear=21; var maxForDay=31;//Leap years are not excluded for(var i=1;i<=12;i ){ var stdYear,stdDay; var stdMonth=getStandardDate(i); /* if(getReverseDate(stdMonth)>maxForDay){ continue; } */ maxForDay=getDate(i); for(var k=1 ;k<maxForDay;k ){ stdDay =getStandardDate(k); stdYear=getReverseDate(stdMonth stdDay); if(parseInt(getReverseDate(stdDay),10)>=minForCentury && parseInt(getReverseDate(stdDay),10)<maxForCentury) theDateList.push(stdYear stdMonth stdDay) } } theDateList.sort(); //Sort for( var i=0;i<theDateList.length;i ){ console.log(theDateList[i]); } console.log('Total %d records',theDateList.length) /** * Calculate the number of days in the current month according to the month * @param {int} val month * @return {int} */ function getDate(val){ return val%2==0?30:31; } /** * Convert date values less than 10 to standard 8-digit date values * @param {int} val month or day * @return {string} standard format */ function getStandardDate(val){ if(val<10){ return '0' val; } return val.toString(); } / ** * Reversed date * @param {string} date The standard format of the month or date * @return {string} The reversed standard format */ function getReverseDate(date){ return date.split("").reverse().join(""); } })(); </script>