为什么我的带有数组的JavaScript代码不起作用？

Question

I am trying to solve the CodeWars Kata: Zeros and Ones. My code solves over 1800 of the Attempt tests and fails just over 100. My problem is that I cannot see the test data because it is so large. To see the test data in other katas I can use a console.log statement. But, the test data in this challenge is too large. I get a list of the first part of an input array followed by "and 400 more items."

Below is a description of the kata and my code along with some test cases. I have tried to create test cases that fail when my code runs them; but, I am unable create any that fail.

• Is my logic sound? Am I missing anything in the logic?
• Can you supply a test case that would fail? (That would be better to help me learn as I would have to analyze my code to fix it.)

Given an array containing only zeros and ones, find the index of the zero that, if converted to one, will make the longest sequence of ones. For instance, given the array... [1,0,1,1,1,0,1,1,1,1,0,1,1,1,1,0,0,1,1], ...replacing the zero at index 10 (counting from 0) forms a sequence of 9 ones. Your task is to write the function replaceZero() that determines where to replace a zero with a one to make the maximum length sub sequence. Note: If the are multiple results, return the last [1,1,0,1,1,0,1,1] //=> 5 The array will always contain zeros and ones.

function replaceZero(arr){

var highestCt = 0;
var returnIdx = 0;

var onesCt = 0;
var currentHighOnesCt = 0;

function countOnes(currentIZ){ // The input should be the current index of the ZERO.
  for(var j = currentIZ - 1; j >= 0; j--){ // Go backwards until a zero is found, or to the beginning of the array.
    if(arr[j] === 1){
      onesCt = onesCt + 1;
    }
    else { // if arr[j] === 0
      break;
    }
  }
  for(var k = currentIZ + 1; k < arr.length; k++){ // Go forwards to a zero or the end of the array.
    if(arr[k] === 1){
      onesCt = onesCt + 1;
    }
    else { // if arr[k] === 0
      break;
    }
  }
  if(onesCt >= currentHighOnesCt){
    currentHighOnesCt = onesCt;
    returnIdx = currentIZ;
  }
  onesCt = 0;
}

for(var i = 0; i < arr.length - 2; i++)
  if(arr[i] === 1 && arr[i + 1] === 0 && arr[i + 2] === 1){
    countOnes(i + 1); // Send the index of the ZERO.
  }

// console.log("returnIdx: " + returnIdx);

return returnIdx;
}

/*
replaceZero([0,0,1,1,1,0,1,1,0,0,1,0]); // 5
replaceZero([0,0,0,1,1,1,0,1,1,0,0,0]); // 6
replaceZero([1,1,1,1,0,1]); // 4
*/
replaceZero([1,0,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,1]); // 9
replaceZero([1,0,0,0,1,0,1,1]); // 5

/*
replaceZero([0,0,1,1,1,1,0,1,1,1,0,1,1,0,0,1,1,0,1,1,0,1,1]); // 6
replaceZero([0,0,1,0,0,1,1,1,0,1,1,0,0,1,1,0,1,1,0]); // 8
replaceZero([0,0,1,0,0,1,1,0,1,1,0,0,1,1,1,0,1,1,0]); // 15
replaceZero([1,0,1,1,1,0,1,1,1,1,0,1,1,1,1,0,0,1,1]); // 10;
replaceZero([1,1,0,1,1,0,1,1]); // 5;
replaceZero([1,1,1,0,1,1,0,1,1,1]); // 6);
*/

Answer 1

Alright so, i'm not actually going to refactor your code, but this might help you:

• Why do you assume the Zero you have to change is in between two Ones ? your if statement is flawed in that matter.

your code:

if(arr[i] === 1 && arr[i + 1] === 0 && arr[i + 2] === 1){ //WHY IN BETWEEN??
  countOnes(i + 1); // Send the index of the ZERO.
}

• Having the above in mind, the following scenarios will fail:

Code:

replaceZero([0,0,0,0,0,0,1]); // 0
replaceZero([0,0,0,0,0,1,1]); // 0
replaceZero([0,0,0,0,1,1,1]); // 0
//.. and so on
//Also
replaceZero([1,1,1,1,1,0,0]); // 0
replaceZero([1,1,1,1,0,0,0]); // 0

and don't be surprised if there is a test for [0,0,0,0,0,0,0] in this case the last index in the array is the expected answer.