<pre class="shiki github-dark shaku"><code>/** * @param {string} str * @return {string} */function longestUniqueSubstr(str) { // your code here let slowIndex = 0; let fastIndex = 0; let myMap = new Map(); let len = 0; let subIndex = 0; while (fastIndex &lt; str.length) { if (myMap.has(str[fastIndex])) { slowIndex = Math.max(slowIndex, myMap.get(str[fastIndex]) + 1); } myMap.set(str[fastIndex], fastIndex); // len = Math.max(len, fastIndex - slowIndex + 1); if (len &lt; fastIndex - slowIndex + 1) { subIndex = slowIndex; len = fastIndex - slowIndex + 1; } fastIndex++; } return str.substring(subIndex, subIndex + len);}console.log(longestUniqueSubstr('pwwkew')) // return sub;</code></pre>

Using Map

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Given a string, please find the longest substring that has no repeated characters. If there are multiple result, any one substring is fine. longestUni…