binary_search.js

let cmp = function(a, b){
    if(a < b) return -1;
    if(a > b) return 1;
    return 0;
};

function bsearch(arr, value, comparator) {
    let low = 0,
        high = arr.length - 1,
        mid;

    while (low <= high) {
        mid = Math.floor((low + high) / 2);
        let result = comparator(arr[mid], value);

        if (result > 0) high = mid - 1;
        else if (result < 0) low = mid + 1;
        else return mid;
    }

    return -1;
}

console.log(bsearch([1,2,3,4,5,6], 6, cmp));

binary_tree_traversal.js

let html = `
<div id="start" class="a">
  <div class="aa">
      <span class="aaa">
        hello
      </span>
      <span class="aab">
      </span>
  </div>
  <div class="ab">
      <span class="aba">
      </span>
      <span class="abb">
        <span class="abb2">
          <span class="abb3">
          </span>
        </span>
      </span>
  </div>
</div>
`

function bfs(startNode, callback) {
  const historyQueue = []
  const visited = []

  historyQueue.push(startNode)

  while(historyQueue.length) {
    let currNode = historyQueue.shift()

    if (currNode == null) continue
    if (visited.includes(currNode)) continue

    visited.push(currNode)

    callback(currNode)

    for (let node of Array.from(currNode.children)) {
      historyQueue.push(node)
    }
  }
}

function dfs(startNode, callback) {
  const historyStack = []
  const visited = []

  historyStack.push(startNode)

  while(historyStack.length) {
    let currNode = historyStack.pop()

    if (currNode == null) continue
    if (visited.includes(currNode)) continue

    visited.push(currNode)

    callback(currNode)

    for (let node of Array.from(currNode.children)) {
      historyStack.push(node)
    }
  }
}