vector<string> generatePalindromes(string s) {
vector<string> ans;
if (s.length() == 1) ans.push_back(s);
if (s.length() <= 1) return ans;
const int SIZE = 256;
int ct[SIZE] = {0}, len = s.length();
for (int i = 0; i < len; ++ i) ++ ct[s[i]];
// count number of each char,
// and get the index of the char of odd occurrence.
int odd = 0, odd_index = 0;
for (int i = 0; i < SIZE; ++ i) {
if (ct[i] & 1) {
odd ++;
odd_index = i;
}
}
// iff can have palindromes, get such strings.
if (((len & 1 == 1) && odd == 1) || (odd == 0)) {
vector<int> nums = getChars(ct, SIZE); // get half of the chars.
sort(nums.begin(), nums.end());
do {
ans.push_back(getPalindrome(nums, len & 1 == 1, odd_index));
} while (nextPermutation(nums));
}
return ans;
}
int main()
{
FILE *fin=fopen("pprime.in","r");
FILE *fout=fopen("pprime.out","w");
fscanf(fin,"%d%d",&a,&b);
if(a<100)
{
if(a<=5)fprintf(fout,"5\n");
if(a<=7)fprintf(fout,"7\n");
if(a<=11)fprintf(fout,"11\n");
a=101;
if(b<100)
{
b=101;
}
}
int num=initPalindrome(a);
while(true)
{
int temp=getPalindrome(num);
if(temp<a or temp>b)
{
break;
}
if(isPrime(temp))
{
fprintf(fout,"%d\n",temp);
}
num++;
}
return 0;
}
void Menu::executePALINDROME() {
int nMin = 0, nMax = 0;
cout << "\tPalindrome 수 구하기 함수를 선택하셨습니다. 범위를 입력해주세요." << endl;
cout << "- 최소값 : ";
cin >> nMin;
cout << "- 최소값 : ";
cin >> nMax;
int cnt = getPalindrome(nMin, nMax);
cout << "▶ 범위 " << nMin << " ~ " << nMax << " 사이의 Palindrome 수의 개수는 " << cnt << "개 입니다." << endl;
}
/**
* function: longestPalindrome
* description: for a given string 'str' return the longest palindrome string
* that is its subset.
**/
void longestPalindrome(char *str, char *palindrome) {
/* 1. check input arguments */
if (str == NULL) { return; }
int maxstart, maxlen;
int center, start, end, len;
bzero(palindrome, MAXLEN); /* zero out the output buffer */
maxstart = 0; maxlen = 1; /* initial palindrome: first letter */
/* check if each position in str is the center of a palindrome */
for (center = 0; center < strlen(str) - 1; center++) {
/* get for odd-length palindrome */
getPalindrome(str, center, center, &start, &end);
/* save info if this is the longest palindrome yet */
len = end - start + 1;
if (len > maxlen) {
maxlen = len;
maxstart = start;
}
/* get for even-length palindrome (hint: it has two centers} */
if (str[center] == str[center+1]) {
getPalindrome(str, center, center+1, &start, &end);
/* save info if this is the longest palindrome yet */
len = end - start + 1;
if (len > maxlen) {
maxlen = len;
maxstart = start;
}
}
}
/* copy longest found palindrome to the output buffer */
strncpy(palindrome, str+maxstart, maxlen);
}
int largestPalindrome(int n) {
if (n == 1) return 9;
uint64_t max_n = 1;
for (int i = 0; i < n; ++i) {
max_n *= 10;
}
max_n--;
uint64_t min_n = (max_n + 1) / 10;
for (uint64_t a = max_n; a >= min_n; --a) {
uint64_t u = getPalindrome(a, n);
//printf("try u = %llu\n", (unsigned long long)u);
double limit = sqrt(u);
for (uint64_t b = max_n; b >= limit; b--) {
if (u % b == 0) {
//printf("b = %u\n", (int)b);
return u % 1337;
}
}
}
}
int initPalindrome(int number)
{
char s[100];
sprintf(s,"%d",number);
int len=(strlen(s)+1)/2;
int res=0;
for(int i=0;i<len;i++)
{
res=res*10+s[i]-'0';
}
while(true)
{
int temp=getPalindrome(res);
if(temp>=a and temp<=b)
{
return res;
}
res++;
}
}
