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  1.  
  2.  
  3. #include <stdio.h>
  4. #include <stdlib.h>
  5. #include <string.h>
  6.  
  7. int main()
  8. {
  9.     int  t , i;    // t = number of test cases , i = a temporary variable for iteration purpose
  10.     char *input , *output ; 
  11.     unsigned long long int l , x , y , mid  ;  // l = length of input string , x = to iterate from mid to start , 
  12. 					       // y = to iterate from mid to end
  13. 					       // mid = middle location of input string (even : l/2-1 , odd : l/2)
  14.     scanf("%d",&t);
  15.  
  16.     while (t--)
  17.     {
  18.         input = (char *)malloc(1000000);
  19.         scanf("%s",input);
  20.         l = strlen(input);
  21.  
  22. 	//check if input is single digit
  23. 	if(l==1)
  24. 	{
  25. 		printf("11\n");
  26. 		break;
  27. 	}
  28. 	//check if input is already a palindrome of kind '99','99','9999',etc. so that output becomes : '101' , '10001'
  29.         i = 0 ;
  30.         for(i = 0 ; i< l ; i++)
  31.         {
  32.                     if(input[i]!='9')
  33.                         break;
  34.         }
  35.  
  36.         if(i==l)
  37.         {
  38.             output = malloc(l+2);
  39.             output[0]='1';
  40.             output[l]='1';
  41.             for(i=1;i<l;i++)
  42.                 output[i]='0';
  43.             output[l+1]='\0';
  44.             printf("%s\n",output);
  45.             break;
  46.         }
  47.  
  48.  
  49.         //make a string containig all digits of input
  50.         output = malloc(l);
  51.         strcpy(output,input);
  52.  
  53.            //find the mid number
  54.             l = strlen(output);
  55.             output[l-1]=output[l-1]+1;
  56.             if (l%2==0)
  57.             {
  58.                 //even
  59.                 mid = l/2 ;
  60.                 x = mid - 1 ;
  61.                 y = mid ;
  62.  
  63. 		//scan until the last the element , and if break appears then start copying the remaining elements
  64. 		// as shown in [1]
  65.             while (y!=l)
  66.                 {
  67.                         //check if first half element is less than second half element , 
  68. 			// if yes , it means the first half element needs to be increased by 1 and second half      //element is made equal to first half element, Ex : 2473 : 2553
  69. //condition(1)	
  70. 		if (output[x] < output[y])
  71.                        {
  72.                         output[x]=output[x]+1 ;
  73.                         output[y]=output[x];
  74.                         break ;
  75.  
  76.                     }
  77. 			//if the two elements are already  equal as in '236679' , '6' == '6' , then we check for
  78. 			// '3' and '7' 
  79. //condition(2)          
  80. 		 else if (output[x] == output[y] && output[x] != '\0')
  81.                     {
  82.                         x--;
  83.                         y++;
  84.                         if(output[x] < output[y])   //if less , then we do the same as condition(1)
  85.                         {
  86.                                 output[x+1] = output[x+1]+1;
  87.                                 output[y-1] = output[y-1]+1;
  88.                         }
  89. 				//no break , so that we can check for next elements
  90.                     }
  91. //special case for handling 9s 
  92. 		 else if (output[x] == '9' && output[y]== '9')
  93.                     {
  94.                         while (output[x]== output[y])           //case like '199999'
  95.                         {
  96.                             x--;
  97.                             y++;
  98.  
  99.                         }
  100.  
  101.                         if (output[x] < output[y])                         //same as condition(1) 
  102.                         {
  103.                                 output[x]=output[x]+1;
  104.                                 output[y]=output[x];
  105.                                 for (i=x+1; i<=y-1; i++)                  // but also replace the 9s with 0
  106.                                     output[i]='0';
  107.                         }
  108.                         break;
  109.                      }
  110. //condition(4)
  111.                     else if (output[x] > output[y])                       //if first half element is greater than //second half element , then simply replace the second half element with first half element                   
  112.                     {
  113.                         output[y]=output[x];
  114.                         break ;
  115.                     }
  116.  
  117.                     x--;
  118.                     y++;
  119.                  }
  120. //start copying unscanned elements of first half elements to second half elements
  121.                 while (y <= l-1 )
  122.                 {
  123.                     output[y]=output[x];
  124.                     x--;
  125.                     y++;
  126.                 }
  127.  
  128.             }
  129.             else
  130.             {
  131.                 //odd
  132.                 mid = l/2 ;
  133.                 x = mid - 1 ;
  134.                 y = mid + 1;
  135.  
  136.                 while (y!=l)
  137.                 {
  138.                     if (output[x] <= output[y] && output[mid] != '9')
  139.                     {
  140.                         output[mid]=output[mid]+1;
  141.                         break ;
  142.                     }
  143.                     else if (output[x] <= output[y] && output[mid] == '9')
  144.                     {
  145.                         while (output[x] == output[y])
  146.                         {
  147.                             x--;
  148.                             y++;
  149.  
  150.                         }
  151.  
  152.                         if (output[x] < output[y])                         // 14897 case
  153.                         {
  154.                             output[x]=output[x]+1;
  155.                             output[y]=output[x];
  156.                             for (i=x+1; i<=y-1; i++)
  157.                                 output[i]='0';
  158.                         }
  159.                         break;
  160.                     }
  161.                     else if (output[x] > output[y])
  162.                     {
  163.                         output[y]=output[x];
  164.                         break ;
  165.                     }
  166.  
  167.                     x--;
  168.                     y++;
  169.                 }
  170.  
  171.                  while (y <= l-1 )
  172.                 {
  173.                     output[y]=output[x];
  174.                     x--;
  175.                     y++;
  176.                 }
  177.  
  178.  
  179.  
  180.             }
  181.  
  182.  
  183.  
  184.             //check
  185.             x = 0 ;
  186.             y = l -1 ;
  187.             while(output[x]==output[y] && output[x] != '\0')
  188.             {
  189.                 x++;
  190.                 y--;
  191.             }
  192.             if(x-1 == l-1)
  193.             {
  194.                 printf("%s\n",output);
  195.             }
  196.  
  197.  
  198.  
  199.  
  200.         }
  201.  
  202.     free(input);
  203.     free(output);
  204.  
  205.     return 0 ;
  206. }
  207.  
Success #stdin #stdout 0s 1924KB
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https://ideone.com/qlP4eL
language:
C (gcc 8.3)
created:
11 years ago
visibility:
public

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