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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. int myStrlen(char s[]){
  5.     int i;
  6.     for(i=0; s[i] != '\0'; i++);
  7.     return i;
  8. }
  9.  
  10. // 部分文字列が回文かどうかを判定
  11. int isPalindrome(char s[], int start, int end){
  12.     while(start < end){
  13.         if(s[start] != s[end]) return 0;
  14.         start++;
  15.         end--;
  16.     }
  17.     return 1;
  18. }
  19.  
  20. char *setPalindrome(char s[]){
  21.     int len = myStrlen(s);
  22.     int addIndex = 0;
  23.  
  24.     for(int i = 0; i < len; i++){
  25.         if(isPalindrome(s, i, len-1)){
  26.             addIndex = i;
  27.             break;
  28.         }
  29.     }
  30.  
  31.     int addLen = addIndex; 
  32.     int newLen = len + addLen;
  33.  
  34.     char *tmp = (char *)malloc((newLen + 1) * sizeof(char));
  35.     if(tmp == NULL){
  36.         printf("Memory allocation failed\n");
  37.         exit(1);
  38.     }
  39.  
  40.     for(int i = 0; i < len; i++){
  41.         tmp[i] = s[i];
  42.     }
  43.  
  44.     for(int i = 0; i < addLen; i++){
  45.         tmp[len + i] = s[addIndex - 1 - i];
  46.     }
  47.  
  48.     tmp[newLen] = '\0';
  49.     return tmp;
  50. }
  51.  
  52. int main(){
  53.     char nyuryoku[1024]; 
  54.     char *kaibun;   
  55.     scanf("%s", nyuryoku);
  56.     kaibun = setPalindrome(nyuryoku);
  57.     printf("%s\n  -> %s\n", nyuryoku, kaibun);
  58.     free(kaibun);
  59.     return 0;
  60. }
Success #stdin #stdout 0.01s 5316KB
comments (?)
stdin 
abab
stdout 
abab
  -> ababa
https://ideone.com/EcFFqt
language:
C (gcc 8.3)
created:
2 days ago
visibility:
public

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