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1 file changed, 74 insertions
dpal.c(file created)
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| 1 | + | #include <stdio.h> | |
| 2 | + | #include <string.h> | |
| 3 | + | #include <stdlib.h> | |
| 4 | + | ||
| 5 | + | char* rev(char buf[]) { | |
| 6 | + | for (int i = 0; i < strlen(buf); i++) { | |
| 7 | + | char t = buf[i]; | |
| 8 | + | buf[i] = buf[strlen(buf) - i - 1]; | |
| 9 | + | buf[strlen(buf) - i - 1] = t; | |
| 10 | + | } | |
| 11 | + | return buf; | |
| 12 | + | } | |
| 13 | + | ||
| 14 | + | char* convertToBase(int number, int base, char buf[]) { | |
| 15 | + | int idx = 0; | |
| 16 | + | char c[2]; | |
| 17 | + | while (number > 0) { | |
| 18 | + | sprintf(c, "%d", number % base); | |
| 19 | + | // if we were converting the base of anything bigger than | |
| 20 | + | // base10, we would have needed a special function to return | |
| 21 | + | // A - F for hexadecimal formats. | |
| 22 | + | buf[idx++] = c[0]; | |
| 23 | + | number /= base; | |
| 24 | + | } | |
| 25 | + | buf[idx] = '\0'; | |
| 26 | + | // we'll have to reverse the string before returning it, | |
| 27 | + | // because we're dividing the original number from the "one's" place -- remainder of | |
| 28 | + | // number % base is always the least significant bits | |
| 29 | + | return rev(buf); | |
| 30 | + | } | |
| 31 | + | ||
| 32 | + | int isPalindrome(char* str) { | |
| 33 | + | int ptra = 0; | |
| 34 | + | int ptrb = strlen(str) - 1; | |
| 35 | + | while (ptra <= ptrb) { | |
| 36 | + | if (str[ptra] != str[ptrb]) { | |
| 37 | + | return 0; | |
| 38 | + | } | |
| 39 | + | ptra++; | |
| 40 | + | ptrb--; | |
| 41 | + | } | |
| 42 | + | return 1; | |
| 43 | + | } | |
| 44 | + | ||
| 45 | + | int main() { | |
| 46 | + | int S = 25; | |
| 47 | + | int N = 3; | |
| 48 | + | ||
| 49 | + | int len = N; | |
| 50 | + | int* palindromeNums = (int*)malloc(len * sizeof(int)); | |
| 51 | + | int idx = 0; | |
| 52 | + | char buf[100]; | |
| 53 | + | ||
| 54 | + | while (N >= 0) { | |
| 55 | + | int cnt = 0; | |
| 56 | + | for (int i = 2; i < 11; i++) { | |
| 57 | + | char* retStr = convertToBase(S, i, buf); | |
| 58 | + | if (isPalindrome(retStr)) { | |
| 59 | + | cnt++; | |
| 60 | + | } | |
| 61 | + | if (cnt > 1) { | |
| 62 | + | palindromeNums[idx++] = S; | |
| 63 | + | break; | |
| 64 | + | } | |
| 65 | + | } | |
| 66 | + | S++; | |
| 67 | + | N--; | |
| 68 | + | } | |
| 69 | + | ||
| 70 | + | for (int i = 0; i < len; i++) { | |
| 71 | + | printf("%d\n", palindromeNums[i]); | |
| 72 | + | } | |
| 73 | + | ||
| 74 | + | } | |
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