javascript - 相同的生日概率代码值不是预期的

Question

有一个名为 Same Birthday Probabilty 的代码战挑战挑战是:

Given n number of people in a room, calculate the probability that any two people in that room have the same birthday (assume 365 days every year = ignore leap year). Answers should be two decimals unless whole (0 or 1) eg 0.05

我为这个挑战做了以下工作:

function calculateProbability(n){
var result = 0;
  for(i=1;i<n;i++){
      var total = (365 - i) / 365
      result = result * total 
  }
  return Math.round(result)
}

使用和不使用 Math.round 方法，但我总是得到:

✘ Value is not what was expected

and that is the only error.

这就是测试用例

Test.expect(calculateProbability(5)==0.03);
Test.expect(calculateProbability(1000)==1);

Answer 1

首先，您应该将结果更改为 1，因为乘以 0 的结果始终为零。您正在计算的结果是解决方案的补充，它是 n 人生日不同的概率。最后，您没有将数字四舍五入到小数点后两位。

function calculateProbability(n){
var result = 1;
  for(i=1;i<n;i++){
      var total = (365 - i) / 365
      result = result * total 
  }
  return Math.round((1-result)*100 )/100
}