I am given a lower limit and an upper limit.. (integers)
I am given a palindrome in this interval..
I am supposed to find the next palindrome in this interval
...
Cud think of something for smaller intervals when I know the number of digits in the number is 3,4,5...
Can some one give a generic method if the upper limit is given to be of the order 10^5..
In the middle of difficulty, lies opportunity
Was there a question in there?
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
In that case you'll probably want to use longs.the upper limit is given to be of the order 10^5
Finding the next palindrome is pretty easy. Say you have the number 123321; in that case, the next palindrome would be 124421. For 12321, it would be 12421. If you count the digits in the original palindrome you can figure out the middle digit[s] and increment them.
It's a little harder when the number's something like 15951. You have to check if the middle number[s] are 9; if they are, increment the next columns: 16061.
You also have to handle a number like 999, which would become 1001. You'd probably want a special case for this, when all the digits are 9.
Hope this helps.
dwk
Seek and ye shall find. quaere et invenies.
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A brute force approach would be
Starting N
Convert N to a string using sprintf (Nstr)
Check if Nstr is a "palindrome string"
Increase N and go back to the first until your final condition
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http://www.uberum.com
Well, that would be pretty silly. But yes, it's one way to do it.
dwk
Seek and ye shall find. quaere et invenies.
"Simplicity does not precede complexity, but follows it." -- Alan Perlis
"Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
"The only real mistake is the one from which we learn nothing." -- John Powell
Other boards: DaniWeb, TPS
Unofficial Wiki FAQ: cpwiki.sf.net
My website: http://dwks.theprogrammingsite.com/
Projects: codeform, xuni, atlantis, nort, etc.
[offtopic] Salem -- cool avatar[/offtopic]
You might want to use strings for this -- handling specific digits in an integer may become tricky. You could use strcmp() to check the range as strings can't use the normal operators.
Code:#include <stdio.h> void J(char*a){int f,i=0,c='1';for(;a[i]!='0';++i)if(i==81){ puts(a);return;}for(;c<='9';++c){for(f=0;f<9;++f)if(a[i-i%27+i%9 /3*3+f/3*9+f%3]==c||a[i%9+f*9]==c||a[i-i%9+f]==c)goto e;a[i]=c;J(a);a[i] ='0';e:;}}int main(int c,char**v){int t=0;if(c>1){for(;v[1][ t];++t);if(t==81){J(v[1]);return 0;}}puts("sudoku [0-9]{81}");return 1;}
