Question

我试图写一个合并两个排序数组a和b的函数。但是，当数组b为0时，它只显示数组a作为输出：

function mergeSortedArrays(a,b) {
  var merged = [],
  aElm = a[0],
  bElm = b[0],
  i = 1, //index for array a
  j = 1; //index for array b

  if (a.length == 0) {
    return b;
  }
  if (b.length == 0) {
    return a;
  }

  while (aElm || bElm) {
    if ((aElm && !bElm) || aElm < bElm) { //problem is that it thinks that 0 == !bElm
      merged.push(aElm);
      aElm = a[i++];
    } else {
      merged.push(bElm);
      bElm = b[j++];
    }
  }
  return merged;
}
mergeSortedArrays([2,5,6,9], [0,1,2,3,29]) //outputs [2,5,6,9]

我理解问题是因为0是假的，所以在条件if(aElm && !bElm)下，它只是不断地将aElm推入merged。什么是更好的编写条件的方法，以便它将0识别为整数而不是不存在？

Answer 1

什么是更好的编写条件的方法，以便它将0识别为整数而不是不存在？

编写条件的更好方法是不测试数组元素的存在，而是检查索引。

function mergeSortedArrays(a,b) {
  var merged = [],
      i = 0, //index for array a
      j = 0; //index for array b

  while (i < a.length || j < b.length) {
    if (j == b.length || a[i] < b[j]) {
      merged.push(a[i++]);
    } else {
      merged.push(b[j++]);
    }
  }
  return merged;
}

Answer 2

您可以明确检查undefined值。

function mergeSortedArrays(a, b) {
    var merged = [],
        aElm = a[0],
        bElm = b[0],
        i = 1, //index for array a
        j = 1; //index for array b

    if (a.length == 0) {
        return b;
    }
    if (b.length == 0) {
        return a;
    }

    while (aElm !== undefined || bElm !== undefined) {
        if ((aElm !== undefined && bElm === undefined) || aElm < bElm) {
            merged.push(aElm);
            aElm = a[i++];
        } else {
            merged.push(bElm);
            bElm = b[j++];
        }
    }
    return merged;
}

console.log(mergeSortedArrays([2, 5, 6, 9], [0, 1, 2, 3, 29]));

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

如果没有负数

，请> -1作为(aElm >-1) && !(bElm>-1)

＆＃13;

function mergeSortedArrays(a,b) {
  var merged = [],
  aElm = a[0],
  bElm = b[0],
  i = 1, //index for array a
  j = 1; //index for array b

  if (a.length == 0) {
    return b;
  }
  if (b.length == 0) {
    return a;
  }

  while ((aElm >-1) || (bElm>-1)) {
    if (((aElm >-1) && !(bElm>-1)) || aElm < bElm) { //problem is that it thinks that 0 == !bElm
      merged.push(aElm);
      aElm = a[i++];
    } else {
      merged.push(bElm);
      bElm = b[j++];
    }
  }
  return merged;
}
var result = mergeSortedArrays([2,5,6,9], [0,1,2,3,29]) //outputs [2,5,6,9]
console.log(result);

＆＃13;

这个解决方案呢

＆＃13;

var a = [2,5,6,9];
var b = [0,1,2,3,29];

a = a.concat(b);
a.sort(function(a, b){return a - b});
console.log(a);

＆＃13;

当第二个数组为0时，无法在JavaScript中合并两个排序的数组

3 个答案: