Check if the next move is check-mate - c++

Question

I am trying to check if the next move of the knight will threaten both kind and queen at the same time, if there's such position it will output YES and the position, otherwise it will be NO.
The input will contain only K for king, Q for queen, and N for knight, and they won't be repeated more than once.
Sample input :
........
........
........
...K....
....Q...
........
N.......
........
this input for example indicates that the knight is 2A , Queen is in 4E ,King is in 5D .
here's my code :
#include <cmath>
#include <stdio.h>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <ctype.h>
#include <fstream>
#include <cstddef>
#include <sstream>
#include<string.h>
#include<cstring>
#include<map>
#include<algorithm>
using namespace std;
int main ()
{
string temp ;
bool flag1 = false , flag2 = false ;
int row1 = 0 , col1 = 0 , row2 = 0 , col2 = 0 ;
int ik=0 , jk=0 , iq=0 , jq=0 , in=0 , jn=0 , i = 8 ;
while ( std::getline (std::cin,temp) )
{
for (int j = 0 ; j<=7 ; j++)
{
if(temp[j] == 'K')
{ ik = i ; jk = j+1 ; }
else if(temp[j] == 'Q')
{ iq = i ; jq = j+1 ; }
else if(temp[j] == 'N')
{ in = i ; jn = j+1 ; }
}
i-- ;
}
// j for columns , i for rows
// if jk = 1 means A , =2 means B , and so on
int threatk[8][2] = {0} , threatq[8][2]= {0} , expn[8][2] = {0} ;
// columns first ( position 0 )
// rows second ( position 1 )
threatk[0][0] = jk+1 ;
threatk[0][1] = ik+2 ;
threatk[1][0] = jk+1 ;
threatk[1][1] = ik-2 ;
threatk[2][0] = jk+2 ;
threatk[2][1] = ik+1 ;
threatk[3][0] = jk+2 ;
threatk[3][1] = ik-1 ;
threatk[4][0] = jk-1 ;
threatk[4][1] = ik+2 ;
threatk[5][0] = jk-1 ;
threatk[5][1] = ik-2 ;
threatk[6][0] = jk-2 ;
threatk[6][1] = ik+1 ;
threatk[7][0] = jk-2 ;
threatk[7][1] = ik-1 ;
threatq[0][0] = jq+1 ;
threatq[0][1] = iq+2 ;
threatq[1][0] = jq+1 ;
threatq[1][1] = iq-2 ;
threatq[2][0] = jq+2 ;
threatq[2][1] = iq+1 ;
threatq[3][0] = jq+2 ;
threatq[3][1] = iq-1 ;
threatq[4][0] = jq-1 ;
threatq[4][1] = iq+2 ;
threatq[5][0] = jq-1 ;
threatq[5][1] = iq-2 ;
threatq[6][0] = jq-2 ;
threatq[6][1] = iq+1 ;
threatq[7][0] = jq-2 ;
threatq[7][1] = iq-1 ;
expn[0][0] = jn+1 ;
expn[0][1] = in+2 ;
expn[1][0] = jn+1 ;
expn[1][1] = in-2 ;
expn[2][0] = jn+2 ;
expn[2][1] = in+1 ;
expn[3][0] = jn+2 ;
expn[3][1] = in-1 ;
expn[4][0] = jn-1 ;
expn[4][1] = in+2 ;
expn[5][0] = jn-1 ;
expn[5][1] = in-2 ;
expn[6][0] = jn-2 ;
expn[6][1] = in+1 ;
expn[7][0] = jn-2 ;
expn[7][1] = in-1 ;
for ( int a = 0 ; a<=7 ; a++)
{
for ( int b=0 ; b<=7 ; b++)
{
if ( ( expn[a][0] == threatk[b][0] && expn[a][1] == threatk[b][1] ) )
{ flag1 = true ; col1 = expn[a][0] ; row1 = expn[a][1] ; }
}
}
for ( int a = 0 ; a<=7 ; a++)
{
for ( int b=0 ; b<=7 ; b++)
{
if ( ( expn[a][0] == threatq[b][0] && expn[a][1] == threatq[b][1] ) )
{ flag2 = true ; col2 = expn[a][0] ; row2 = expn[a][1] ; }
}
}
if ( ( flag1 && flag2 ) && ( col1 >= 1 && col1 <= 8 && row1 >= 1 && row1 <= 8)
&& ( col2 >= 1 && col2 <= 8 && row2 >= 1 && row2 <= 8)
&& ( col1 = col2 && row1 = row2) )
{ string out = "" ;
if ( col1 == 1)out = "A" ;
else if ( col1 == 2) out = "B" ;
else if ( col1 == 3) out = "C" ;
else if ( col1 == 4) out = "D" ;
else if ( col1 == 5) out = "E" ;
else if ( col1 == 6) out = "F" ;
else if ( col1 == 7) out = "G" ;
else if ( col1 == 8) out = "H" ;
cout<<"YES"<<" "<<row1<<out ;
}
else cout<<"NO" ;} '
my approach is to get the threat positions for the king and the queen from a knight , and compare with it with the next possible move for the knight
it's working fine but it fails at some tests that am not aware of i just get to know if it passed all the tests or not .
what do you think is wrong ?

Answer 1

When you are designing code, make sure that all parts are easily testable. Design functions that do one clear thing and can be reused easily. Afterwards test them well so you can figure out what part of your code is wrong.
It is very hard to review your code and figure out what could potentially be wrong. I wrote a solution in Python that should pass all possible edge cases and I will share it here. Parsing input and output is not part of it.
N = 8
def generateThreat(y, x):
threats = []
candidate = (y+2, x+1)
if (candidate[0] < N-1 and candidate[1] < N-1):
threats.append(candidate)
candidate = (y+2, x-1)
if (candidate[0] < N-1 and candidate[1] >= 0):
threats.append(candidate)
candidate = (y-2, x+1)
if (candidate[0] >= 0 and candidate[1] < N-1):
threats.append(candidate)
candidate = (y-2, x-1)
if (candidate[0] >= 0 and candidate[1] >= 0):
threats.append(candidate)
candidate = (y+1, x+2)
if (candidate[0] < N-1 and candidate[1] < N-1):
threats.append(candidate)
candidate = (y+1, x-2)
if (candidate[0] < N-1 and candidate[1] >= 0):
threats.append(candidate)
candidate = (y-1, x+2)
if (candidate[0] >= 0 and candidate[1] < N-1):
threats.append(candidate)
candidate = (y-1, x-2)
if (candidate[0] >= 0 and candidate[1] >= 0):
threats.append(candidate)
return threats
def generateAllThreatsFromCurrent(y, x):
all_threats = set()
for next_step in generateThreat(y, x):
all_threats.update(generateThreat(next_step[0], next_step[1]))
return all_threats
def isMatePossible(king, queen, knight):
y, x = knight
all_threats = generateAllThreatsFromCurrent(y, x)
if king in all_threats and queen in all_threads:
return True
return False