Jump Game III LeetCode solution in JavaScript

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// Recursion, Backtracking
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var canReach = function (arr, start) {
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  if (arr === null || arr.length === 0) {
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    return false;
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  }
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  return dfs(arr, start);
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  // T.C: O(N)
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  // S.C: O(N)
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};
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const dfs = (arr, idx) => {
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  if (arr[idx] === 0) {
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    return true;
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  }
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  if (idx < 0 || idx > arr.length - 1 || arr[idx] < 0) {
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    return false;
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  }
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  let jump = arr[idx];
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  arr[idx] = -1; // marking this index as visited
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  return dfs(arr, idx - jump) || dfs(arr, idx + jump);
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};