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/**
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 * @param {number[][]} board
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 * @return {number}
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 */
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var movesToChessboard = function (board) {
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  const boardSize = board.length;
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  const boardSizeIsEven = boardSize % 2 === 0;
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  if (!canBeTransformed(board)) return -1;
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  // to convert to 010101
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  let rowSwap = 0;
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  let colSwap = 0;
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  // to convert to 101010
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  let rowSwap2 = 0;
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  let colSwap2 = 0;
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  for (let i = 0; i < boardSize; i++) {
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    if (board[i][0] === i % 2) {
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      rowSwap++;
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    } else {
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      rowSwap2++;
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    }
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    if (board[0][i] === i % 2) {
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      colSwap++;
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    } else {
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      colSwap2++;
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    }
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  }
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  // no need to swap anything
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  if (rowSwap + colSwap === 0 || rowSwap2 + colSwap2 === 0) return 0;
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  if (boardSizeIsEven) {
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    rowSwap = Math.min(rowSwap, rowSwap2);
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    colSwap = Math.min(colSwap, colSwap2);
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  } else {
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    rowSwap = rowSwap % 2 === 0 ? rowSwap : rowSwap2;
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    colSwap = colSwap % 2 === 0 ? colSwap : colSwap2;
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  }
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  return (rowSwap + colSwap) / 2;
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  function canBeTransformed(board) {
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    // number of 0 and 1 should be equal
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    let sum = board[0].reduce((a, b) => a + b);
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    if (boardSizeIsEven && sum != boardSize / 2) return false;
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    if (!boardSizeIsEven && sum > (boardSize + 1) / 2) return false;
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    let first = board[0].join("");
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    let opposite = board[0].map((item) => (item === 1 ? 0 : 1)).join("");
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    // each row should be equal to first or opposite
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    let counter = [0, 0];
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    for (let i = 0; i < boardSize; i++) {
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      let str = board[i].join("");
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      if (str == first) {
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        counter[0]++;
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      } else if (str == opposite) {
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        counter[1]++;
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      } else {
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        return false;
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      }
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    }
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    // for even board, two types of rows should be equal
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    if (boardSizeIsEven) {
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      return counter[0] == counter[1];
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    }
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    return Math.abs(counter[0] - counter[1]) === 1;
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  }
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};