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## Discussion of Problem 1298. Knight

Help me please
Posted by Roma Labish[Lviv NU] 27 Feb 2007 00:30
I had use Warnsdorff heuristic, but I take wrang answer.. Maybe you can find my bug?

#include <iostream>
using namespace std;

struct minimum
{
int minp;
int i;
int j;
minimum():minp(9999),i(0),j(0){}
};
int d[9][9];
bool isnuje_hid(int i, int j,int n)
{
if(i <= n && i >= 1 && j <= n && j >= 1)
return true;
else
return false;
}
int reytung(int i,int j,int n)
{
int k = 0;
if(!d[i][j])
{
if(isnuje_hid(i+2,j+1,n))k++;
if(isnuje_hid(i+1,j+2,n))k++;
if(isnuje_hid(i+2,j-1,n))k++;
if(isnuje_hid(i+1,j-2,n))k++;
if(isnuje_hid(i-2,j+1,n))k++;
if(isnuje_hid(i-2,j-1,n))k++;
if(isnuje_hid(i-1,j+2,n))k++;
if(isnuje_hid(i-1,j-2,n))k++;
}
else return -1;
return k;
}

void zrobyty_hid(int & i, int & j,int n)
{
minimum a;
if(isnuje_hid(i+2,j+1,n))
if(reytung(i+2,j+1,n) < a.minp && reytung(i+2,j+1,n) > 0)
{
a.minp = reytung(i+2,j+1,n);
a.i = i + 2;
a.j = j + 1;
}
if(isnuje_hid(i+1,j+2,n))
if(reytung(i+1,j+2,n) < a.minp && reytung(i+1,j+2,n) > 0)
{
a.minp = reytung(i+1,j+2,n);
a.i = i + 1;
a.j = j + 2;
}
if(isnuje_hid(i+2,j-1,n))
if(reytung(i+2,j-1,n) < a.minp && reytung(i+2,j-1,n) > 0)
{
a.minp = reytung(i+2,j-1,n);
a.i = i + 2;
a.j = j - 1;
}
if(isnuje_hid(i+1,j-2,n))
if(reytung(i+1,j-2,n) < a.minp && reytung(i+1,j-2,n) > 0 )
{
a.minp = reytung(i+1,j-2,n);
a.i = i + 1;
a.j = j - 2;
}
if(isnuje_hid(i-2,j+1,n))
if(reytung(i-2,j+1,n) < a.minp && reytung(i-2,j+1,n) > 0)
{
a.minp = reytung(i-2,j+1,n);
a.i = i - 2;
a.j = j + 1;
}
if(isnuje_hid(i-2,j-1,n))
if(reytung(i-2,j-1,n) < a.minp && reytung(i-2,j-1,n) > 0)
{
a.minp = reytung(i-2,j-1,n);
a.i = i - 2;
a.j = j - 1;
}
if(isnuje_hid(i-1,j+2,n))
if(reytung(i-1,j+2,n) < a.minp && reytung(i-1,j+2,n) > 0)
{
a.minp = reytung(i-1,j+2,n);
a.i = i - 1;
a.j = j + 2;
}
if(isnuje_hid(i-1,j-2,n))
if(reytung(i-1,j-2,n) < a.minp && reytung(i-1,j-2,n) > 0)
{
a.minp = reytung(i-1,j-2,n);
a.i = i - 1;
a.j = j - 2;
}
if(i && j)
{
i = a.i;
j = a.j;
}
d[i][j] = 1;
}
char convert(int n)
{
switch(n)
{
case 1: return 'a';
case 2: return 'b';
case 3: return 'c';
case 4: return 'd';
case 5: return 'e';
case 6: return 'f';
case 7: return 'g';
case 8: return 'h';
}
}
int main()
{
int n;
cin >> n;
if(n < 5 && n > 1){cout << "IMPOSSIBLE"; return 0;}
int m = 1,k = 1;
d[1][1] = 1;d[0][1] = 1;d[1][0] = 1;d[0][0] = 1;
for(int i = 1; i <= n*n; i++)
{
cout << convert(m) << k << endl;
zrobyty_hid(m,k,n);
}
return 0;
}

Edited by author 27.02.2007 00:32

Edited by author 27.02.2007 02:42
Re: Help me please
Posted by Astekinane 3 Oct 2011 20:33
My algorithm based on Warnsdorff rule got AC. Check your realisation.