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var matrixScore = function (grid) {
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  let flip = (i, rowOrCol) => {
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    // helper function for flipping row and column
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    if (rowOrCol) {
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      for (let idx in grid[i]) {
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        grid[i][idx] = grid[i][idx] === 1 ? 0 : 1;
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      }
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    } else {
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      for (let idx in grid) {
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        grid[idx][i] = grid[idx][i] === 1 ? 0 : 1;
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      }
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    }
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  };
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  for (let i = 0; i < grid.length; i++) {
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    // flip rows only if leftmost bit is 0
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    if (grid[i][0] !== 1) {
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      flip(i, true);
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    }
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  }
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  for (let i = 1; i < grid[0].length; i++) {
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    //flip column only if the number of 1s is less than 0s, as all bits hold equal values in a column
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    let ones = 0;
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    for (let j in grid) {
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      ones += grid[j][i];
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    }
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    if (ones < grid.length / 2) flip(i, false);
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  }
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  return grid.reduce((a, b) => a + parseInt(b.join(""), 2), 0);
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};