Find Words That Can Be Formed by Characters
<p>You are given an array of strings <code>words</code> and a string <code>chars</code>.</p>

<p>A string is <strong>good</strong> if it can be formed by characters from <code>chars</code> (each character can only be used once for <strong>each</strong> word in <code>words</code>).</p>

<p>Return <em>the sum of lengths of all good strings in words</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> words = [&quot;cat&quot;,&quot;bt&quot;,&quot;hat&quot;,&quot;tree&quot;], chars = &quot;atach&quot;
<strong>Output:</strong> 6
<strong>Explanation:</strong> The strings that can be formed are &quot;cat&quot; and &quot;hat&quot; so the answer is 3 + 3 = 6.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> words = [&quot;hello&quot;,&quot;world&quot;,&quot;leetcode&quot;], chars = &quot;welldonehoneyr&quot;
<strong>Output:</strong> 10
<strong>Explanation:</strong> The strings that can be formed are &quot;hello&quot; and &quot;world&quot; so the answer is 5 + 5 = 10.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= words.length &lt;= 1000</code></li>
	<li><code>1 &lt;= words[i].length, chars.length &lt;= 100</code></li>
	<li><code>words[i]</code> and <code>chars</code> consist of lowercase English letters.</li>
</ul>
Array; Hash Table; String; Counting
function countCharacters(words: string[], chars: string): number {
    const idx = (c: string) => c.charCodeAt(0) - 'a'.charCodeAt(0);
    const cnt = new Array(26).fill(0);
    for (const c of chars) {
        cnt[idx(c)]++;
    }
    let ans = 0;
    for (const w of words) {
        const wc = new Array(26).fill(0);
        let ok = true;
        for (const c of w) {
            if (++wc[idx(c)] > cnt[idx(c)]) {
                ok = false;
                break;
            }
        }
        if (ok) {
            ans += w.length;
        }
    }
    return ans;
}
