66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdbool.h>
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#include <math.h>
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void intToDecimalString (int n, char** string) {
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*string = malloc (sizeof (char) * (int)(floor (log10 (n)) + 1));
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sprintf (*string, "%d", n);
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}
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void intToBinaryString (int n, char** string) {
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char hex[9];
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sprintf (hex, "%x", n);
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char bins[16][5] = { "0000", "0001", "0010", "0011",
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"0100", "0101", "0110", "0111",
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"1000", "1001", "1010", "1011",
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"1100", "1101", "1110", "1111" };
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*string = malloc (sizeof (char) * 33);
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(*string)[0] = '\0';
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for (int c = 0; c < 9; c++) {
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if (hex[c] >= '0' && hex[c] <= '9') {
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strcat (*string, bins[hex[c] - '0']);
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}
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else if (hex[c] >= 'a' && hex[c] <= 'z') {
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strcat (*string, bins[hex[c] - 'a' + 0xa]);
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}
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}
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}
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bool isPalindrome (char* string) {
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int index = 0;
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while (string[index] == '0')
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index++;
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bool palindromic = true;
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int len = strlen (string);
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for (int i = 0; i < (len - index) / 2; i++) {
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if (string[index + i] != string[len - i - 1]) {
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palindromic = false;
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break;
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}
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}
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return palindromic;
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}
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int main () {
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int sum = 0;
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for (int i = 1; i < 1000000; i++) {
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char* decimal;
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intToDecimalString (i, &decimal);
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char* binary;
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intToBinaryString (i, &binary);
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if (isPalindrome (decimal) && isPalindrome (binary)) {
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sum += i;
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printf ("%s, %s\n", decimal, binary);
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}
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free (decimal);
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free (binary);
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}
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printf ("%d\n", sum);
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}
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