freeCodeCamp/entropy.md at 4a74567986d8de748f954e8957adc7613e85193f

Oliver Eyton-Williams 4a74567986 fix: remove title from Chinese chals

2020-10-06 23:10:08 +05:30

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id, challengeType, videoUrl, localeTitle

id	challengeType	videoUrl	localeTitle
599d15309e88c813a40baf58	5		熵

Description

任务：

计算给定输入字符串的香农熵H.

给定谨慎的随机变量$ X $，它是$ N $“符号”（总字符）的字符串，由$ n $个不同的字符组成（对于二进制，n = 2），位/符号中X的香农熵是：

$ H_2（X）= - \ sum_ {i = 1} ^ n \ frac {count_i} {N} \ log_2 \ left（\ frac {count_i} {N} \ right）$

其中$ count_i $是字符$ n_i $的计数。

Instructions

Tests

tests:
  - text: <code>entropy</code>是一种功能。
    testString: assert(typeof entropy === 'function');
  - text: <code>entropy("0")</code>应该返回<code>0</code>
    testString: assert.equal(entropy('0'), 0);
  - text: <code>entropy("01")</code>应该返回<code>1</code>
    testString: assert.equal(entropy('01'), 1);
  - text: <code>entropy("0123")</code>应该返回<code>2</code>
    testString: assert.equal(entropy('0123'), 2);
  - text: <code>entropy("01234567")</code>应该返回<code>3</code>
    testString: assert.equal(entropy('01234567'), 3);
  - text: <code>entropy("0123456789abcdef")</code>应返回<code>4</code>
    testString: assert.equal(entropy('0123456789abcdef'), 4);
  - text: <code>entropy("1223334444")</code>应返回<code>1.8464393446710154</code>
    testString: assert.equal(entropy('1223334444'), 1.8464393446710154);

Challenge Seed

function entropy (s) {
  // Good luck!
}

Solution

// solution required

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