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  1. #include<stdio.h>
  2. #include<stdlib.h>
  3. #include<inttypes.h>
  4. #include<string.h>
  5. #include<stdbool.h>
  6. #include<assert.h>
  7.  
  8. #define STRING_LENGTH 1000002
  9.  
  10. bool check_palindrome(char[]);
  11. bool check_all_nines(char[]);
  12. void find_next_palindrome(char[]);
  13.  
  14. int main(void) {
  15.     uint64_t test;
  16.     scanf("%"SCNu64,&test);
  17.     assert(test > 0);
  18.     while(test--) {
  19.         char number_base_10[STRING_LENGTH];
  20.         scanf("%s",number_base_10);
  21.         uint32_t string_len = strlen(number_base_10);
  22.         assert(string_len > 0);
  23.         if(check_all_nines(number_base_10)) {
  24.             for(uint32_t i=0;i<=string_len;++i) {
  25.                 if(i == 0 || i == (string_len)) {
  26.                     number_base_10[i] = '1';
  27.                 } else {
  28.                     number_base_10[i] = '0';
  29.                 }
  30.             }
  31.             string_len++;//as len increases by 1
  32.         } else {
  33.             find_next_palindrome(number_base_10);
  34.         }
  35.         //puts(number_base_10);
  36.         for(int i=0;i<string_len;i++)
  37.         {
  38.             printf("%c",number_base_10[i]);
  39.         }
  40.         printf("\n");
  41.         memset(number_base_10,'\0',sizeof(char)*STRING_LENGTH);
  42.     }
  43.     return 0;
  44. }
  45.  
  46. bool check_all_nines(char number[]) {
  47.     bool is_all_nines = true;
  48.     for(uint32_t i=0;number[i]!='\0';++i) {
  49.         if(!(number[i] == '9')) {
  50.             is_all_nines = false;
  51.             break;
  52.         }
  53.     }
  54.     return is_all_nines;
  55. }
  56.  
  57. bool check_palindrome(char number[]) {
  58.     bool is_palindrome = true;
  59.     for(uint32_t start = 0,end = (strlen(number) - 1);(start < end);++start,--end) {
  60.         if(!(number[start] == number[end])) {
  61.             is_palindrome = false;
  62.             break;
  63.         }
  64.     }
  65.     return is_palindrome;
  66. }
  67.  
  68. void find_next_palindrome(char number[]) {
  69.     uint32_t str_len = strlen(number);
  70.     if(check_palindrome(number)) {
  71.         uint32_t start,mid,end;
  72.         start = 0;
  73.         end = str_len - 1;
  74.         mid = ((end - start) >> 1) + start;
  75.         for(start = mid,(end = (str_len & 1) ? mid : (mid + 1)); (start >= 0 && end < str_len) && (number[start] == '9'); --start,++end) {
  76.             number[end] = number[start] = '0';
  77.         }
  78.         if(start >= 0 && end < str_len) {
  79.             number[start]++;
  80.             number[end] = number[start];
  81.         }
  82.     } else {
  83.         uint32_t start,mid,end;
  84.         bool flag = false;
  85.         start = 0;
  86.         end = str_len - 1;
  87.         mid = ((end - start) >> 1) + start;
  88.         for(start = mid, end = ((str_len & 1) ? mid: (mid + 1)); (start >=0 && end < str_len) && (number[start] == number[end]); --start,++end);
  89.         if(number[start] < number[end]) {
  90.             flag = true;
  91.             number[end] = number[start];
  92.         }
  93.         if(flag) {
  94.             for(start = mid, end = ((str_len & 1) ? mid : (mid + 1)); (start >=0 && end < str_len) && (number[start] == '9'); --start,++end) {
  95.                 number[end] = number[start] = '0';
  96.             }
  97.             if(start >=0 && end < str_len) {
  98.                 number[start]++;
  99.                 number[end] = number[start];
  100.             }
  101.         }
  102.         for(start = 0, end = str_len - 1; (start < end); ++start,--end) {
  103.             number[end] = number[start];
  104.         }
  105.     }
  106. }
Success #stdin #stdout 0s 4392KB
comments (?)
stdin
copy 
5
9091
99
999
999999
213
stdout
copy 
9119
101
1001
1000001
222
https://ideone.com/1t8FLv
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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