就是我对原数组排序，复制的数组也跟着排序了。

function validSolution(board){
    let result = {};
    // let copy = [];
    // let copy = board.slice(0);
    let copy = board.concat([]);
    // for(var i=0;i a-b).toString() !== arr.toString()) return false;
    }

    return true;
}


console.log(validSolution([[5, 3, 4, 6, 7, 8, 9, 1, 2],
    [6, 7, 2, 1, 9, 5, 3, 4, 8],
    [1, 9, 8, 3, 4, 2, 5, 6, 7],
    [8, 5, 9, 7, 6, 1, 4, 2, 3],
    [4, 2, 6, 8, 5, 3, 7, 9, 1],
    [7, 1, 3, 9, 2, 4, 8, 5, 6],
    [9, 6, 1, 5, 3, 7, 2, 8, 4],
    [2, 8, 7, 4, 1, 9, 6, 3, 5],
    [3, 4, 5, 2, 8, 6, 1, 7, 9]]));

console.log(validSolution([[5, 3, 4, 6, 7, 8, 9, 1, 2],
    [6, 7, 2, 1, 9, 0, 3, 4, 8],
    [1, 0, 0, 3, 4, 2, 5, 6, 0],
    [8, 5, 9, 7, 6, 1, 0, 2, 0],
    [4, 2, 6, 8, 5, 3, 7, 9, 1],
    [7, 1, 3, 9, 2, 4, 8, 5, 6],
    [9, 0, 1, 5, 3, 7, 2, 1, 4],
    [2, 8, 7, 4, 1, 9, 6, 3, 5],
    [3, 0, 0, 4, 8, 1, 1, 7, 9]]));