[UVa] 12414 - Calculating Yuan Fen

Method: Simulate it, nothing special. But don't handle with strings. TLE for sure then.

#include <stdio.h>

int y(char *s, int st) {
 int val[100], stor[100], v, i, j, k=0;
 for (i=0 ; s[i] ; i++) {
  v = s[i]+st-'A';
  for (j=0 ; v ; j++, v/=10) {
   stor[j] = v%10;
  }
  for (--j ; j>=0 ; j--, k++) {
   val[k] = stor[j];
   
  }
 }
 
 
 while (k>2) {
  for (i=0, j=0 ; j<k ; j++, i++) {
   val[i] = (val[j]+val[j+1])%10;
  }
  if (k==4) {
   if (val[0]==1 && val[1]==0 && val[2]==0) {
    return 100;
   }
  }
  k--;
 }
 return 0;
}

int main( void ) {
 char input[20];
 int i, found, result;
 while ( gets(input) ) {
  
  for (i=1, found=0 ; i<=10000 && found==0 ; i++) {
   result = y(input, i);
   if (result == 100) {
    found = 1;
   }
  }
  if (found == 1) {
   printf("%d\n",i-1);
  } else {
   printf(":(\n");
  }
 }
 return 0; 
}