g0701_0800.s0782_transform_to_chessboard.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g0701_0800.s0782_transform_to_chessboard;
// #Hard #Array #Math #Matrix #Bit_Manipulation
public class Solution {
public int movesToChessboard(int[][] board) {
int n = board.length;
int colToMove = 0;
int rowToMove = 0;
int rowOneCnt = 0;
int colOneCnt = 0;
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (((board[0][0] ^ board[i][0]) ^ (board[i][j] ^ board[0][j])) == 1) {
return -1;
}
}
}
for (int i = 0; i < n; i++) {
rowOneCnt += board[0][i];
colOneCnt += board[i][0];
if (board[i][0] == i % 2) {
rowToMove++;
}
if (board[0][i] == i % 2) {
colToMove++;
}
}
if (rowOneCnt < n / 2 || rowOneCnt > (n + 1) / 2) {
return -1;
}
if (colOneCnt < n / 2 || colOneCnt > (n + 1) / 2) {
return -1;
}
if (n % 2 == 1) {
// we cannot make it when ..ToMove is odd
if (colToMove % 2 == 1) {
colToMove = n - colToMove;
}
if (rowToMove % 2 == 1) {
rowToMove = n - rowToMove;
}
} else {
colToMove = Math.min(colToMove, n - colToMove);
rowToMove = Math.min(rowToMove, n - rowToMove);
}
return (colToMove + rowToMove) / 2;
}
}