I have come across this JavaScript code which seems to be functioning correctly. However, I am curious about the line board[3][8] != board[8][3] and how it checks for repeating row and column numbers. Can someone please provide an explanation? Thank you!
function validSolution(board) {
let count0 = 0;
let count1 = 0;
let count2 = 0;
let count3 = 0;
let count4 = 0;
let count5 = 0;
let count6 = 0;
let count7 = 0;
let count8 = 0;
let count9 = 0;
for (let i = 0; i < board.length; i++) {
count0 += board[i][0];
count1 += board[i][1];
count2 += board[i][2];
count3 += board[i][3];
count4 += board[i][4];
count5 += board[i][5];
count6 += board[i][6];
count7 += board[i][7];
count8 += board[i][8];
}
return (count0 === 45 && count1 === 45 && count2 === 45 && count3 === 45
&& count4 === 45 && count5 === 45 && count6 === 45 && count7 === 45 &&
count8 === 45 && board[3][8] != board[8][3] );
}