tmp_获取下一个回文数
直接拿之前一次竞赛中写的code,稍微完善了点,后面有机会在优化
uint64_t GetNextPalindrome(uint64_t data)
{
//100以内的数字已经特殊考虑过,不存在差值1的两个回文数
//首先得到长度,如果是奇数,取前一半+中间值构造,如果是偶数,取前一半构造
//====================
//添加部分code,得到通用的获取下一个回文数的函数,记录到代码库里面,有需要时候直接拿来用
//函数功能是获取下一个回文数,
//下面的是100意外的部分,这里添加100以内的处理
//if (data < 100)
//{
// if (data < 9)
// {
// //个位数,直接加1
// return data + 1;
// }
// //两位数
//}
//构建表直接返回好了
if (data < 100)
{
vector<int> tmpdata= { 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99,101 };
for (int i = 0; i < tmpdata.size(); i++)
{
if (data < tmpdata[i])
{
return tmpdata[i];
}
}
}
//====================
uint64_t tmpdata = data;
uint64_t length = 0;
while (tmpdata)
{
tmpdata /= 10;
length++;
}
//到这里得到数据长度,根据奇偶判断
if (length % 2 == 0)
{
//偶数长度
uint64_t highhalf;
highhalf = data / (uint64_t)(pow(10, length / 2)); //得到前一半
uint64_t lowhalf;
lowhalf = data % (uint64_t)(pow(10, length / 2)); //低一半
uint64_t tmphigh = GetPallindrom(highhalf);
if (tmphigh > lowhalf)
{
//只需要将高一般构建结果即可
return data + (tmphigh - lowhalf);
}
else
{
highhalf += 1;
uint64_t tmplength = 0;
tmpdata = highhalf;
while (tmpdata)
{
tmpdata /= 10;
tmplength++;
}
if (tmplength == length / 2)
{
//没产生进位
return highhalf*pow(10, tmplength) + GetPallindrom(highhalf);
}
else
{
//返回奇数个的10X01
return highhalf*pow(10, tmplength - 1) + GetPallindrom(highhalf);
}
}
}
else
{
//奇数长度中间+1即可,如果原来是9,变为10XX01
uint64_t highhalf = data / (uint64_t)(pow(10, length / 2));
uint64_t mid = highhalf % 10;
highhalf /= 10;
uint64_t lowhalf = data % (uint64_t)(pow(10, length / 2));
uint64_t tmphighhalf = GetPallindrom(highhalf);
//不需要动到中间位置数组
if (tmphighhalf > lowhalf)
{
return data + (tmphighhalf - lowhalf);
}
//需要更新中间数字
if (mid < 9)
{
return (highhalf * 10 + mid + 1)*pow(10, length / 2) + tmphighhalf;
}
else
{
//高一半+1不进位,只需要高一半+1,该位变0即可,比如191 -> 202
//如果高位+1后需要进位,如99X,则需要变为1001,即最小的高一位
mid = 0;
highhalf += 1;
tmphighhalf = GetPallindrom(highhalf);
uint64_t tmplength = 0;
tmpdata = highhalf;
while (tmpdata)
{
tmpdata /= 10;
tmplength++;
}
if (tmplength == length / 2)
{
//没产生进位
return (highhalf * 10 + mid)*pow(10, length / 2) + tmphighhalf;
}
else
{
//产生了进位 比如999应该变为1001
return highhalf*pow(10, tmplength) + tmphighhalf;
}
}
}
}
uint64_t GetPallindrom(uint64_t data)
{
uint64_t ret = 0;
while (data>0)
{
ret = ret * 10 + data % 10;
data = data / 10;
}
//cout << "debug:" << data << " -> " << ret << endl;;
return ret;
}