之字形打印矩阵

[Sunny-117]

No description provided.

[Tylermeek]

// 之字形输出，即分别输出每条右上左下的对角线，每次的输出顺序相反，
//        从上到下的时候即从右上角输出到左下角，从下到上的时候即从左下角输出到右上角

var a = [
  [11, 42, 23, 41],
  [57, 61, 45, 52],
  [71, 11, 23, 42],
];

function printMartix(martix) {
  // 初始化右上角起点tR、tC；左下角起点bR、bC
  let tR = 0,
    tC = 0,
    bR = 0,
    bC = 0,
    rowLen = martix.length,
    colLen = martix[0].length,
    fromTop = true; // 初始方向为从上到下
  // console.log(rowLen, colLen);
  while (tR < rowLen) {
    // console.log(tR, tC, bR, bC, fromTop);
    printLine(martix, tR, tC, bR, bC, fromTop);
    // 坐标的变化方式，小注意点就是：判断条件的坐标值要放在最后进行处理，否则会导致提前判断越界
    tC === colLen - 1 ? tR++ : tR;
    tC === colLen - 1 ? tC : tC++;
    bR === rowLen - 1 ? bC++ : bC;
    bR === rowLen - 1 ? bR : bR++;
    // 方向反过来
    fromTop = !fromTop;
  }
}

function printLine(martix, tR, tC, bR, bC, fromTop) {
  // 沿着对角线进行输出，起点根据当前方向进行判断即可
  if (fromTop) {
    let r = tR,
      c = tC;
    while (r <= bR && c >= bC) {
      console.log(martix[r++][c--]);
    }
  } else {
    let r = bR,
      c = bC;
    while (r >= tR && c <= tC) {
      console.log(martix[r--][c++]);
    }
  }
}

printMartix(a);

[Windseek]

var a = [
  [11, 42, 23, 41],
  [57, 61, 45, 52],
  [71, 11, 23, 42],
];

const printMatrix = (a) => {
  const rs = [];

  const left2right = (arr) => {
    for(var i = 0; i < arr.length; i++) {
      rs.push(arr[i]);
    }
  };

  const right2left = (arr) => {
    for(var i = arr.length - 1; i >= 0; i--) {
      rs.push(arr[i]);
    }
  };

  for(var i = 0; i < a.length; i++) {
    if(i%2 === 0) {
      left2right(a[i]);
    } else {
      right2left(a[i]);
    }
  }
  return rs;
};

console.log(printMatrix(a));

[Windseek]

const printMatrix = (a) => {
  for(var i = 0; i < a.length; i++) {
    if(i%2 === 1) {
      a[i].reverse();
    }
  }
  return a.flat();
}
console.log(printMatrix(a));