1kohei1

import heapq

class Solution:
    def findKthLargest(self, nums: List[int], k: int) -> int:
        heap = []
        for n in nums:
            heapq.heappush(heap, -n)
            if len(heap) > k:
                # list popは引数がない場合、最後の要素を削除する。その計算量はO(1)
                # https://wiki.python.org/moin/TimeComplexity

1kohei1

class TreeDrawer {
	public static String treeNodeToString(TreeNode root) {
		if (root == null) {
			return "[]";
		}

		String output = "";
		Queue<TreeNode> nodeQueue = new LinkedList<>();
		nodeQueue.add(root);
		while (!nodeQueue.isEmpty()) {

1kohei1

JSON.stringify(undefined); // undefined
JSON.stringify(function() {}); // undefined
JSON.stringify([1, undefined, function() {}, 4]); // "[1,null,null,4]"
JSON.stringify({a: 2, b: function() {}}); // "{"a":2}"

// The second argument is called a replacer. It filters out which will be in stringified JSON
var a = {
	a: 1,
	b: 2,
	c: 3,

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var a = new String('abc');
a.__proto__ === String.prototype; // true
- a.__proto__.constructor === String; // true

// JS internal [[Class]] can be revealed by calling Object.prototype.toString
Object.prototype.toString.call([1,2,3]); // "[object Array]"
Object.prototype.toString.call(/regex-literal/i); // "[object RegExp]"
Object.prototype.toString.call(null); // "[object Null]"
Object.prototype.toString.call(undefined); // "[object Undefined]"
// There are no Null() nor Undefined(), but still there are internal constructor

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function foo(x) {
	x.push(4);
	console.log(x); // [1,2,3,4];

	x = [4,5,6];
	x.push(7);
	console.log(x); // [4,5,6,7]
}
var a = [1,2,3];
foo(a);

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void 2; // undefined
void 'abc'; // undefined
void function() {}; // undefined
void undefined; // undefined
void null; // undefined
void {}; // undefined
void true; // undefined
void false; // undefined

// NaN means "Not a Number", however the type of NaN is a "number"

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function foo() {
	var undefined = 2;
	console.log(undefined); // 2
}
foo();

// In strict mode, this is also valid
function foo() {
	'use strict';
	var undefined = 2;

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42.toFixed(3); // SyntaxError
// This is invalid since it first recognizes . as fraction point. 

(42).toFixed(3); // "42.000"
0.42.toFixed(3); // "0.420"
42..toFixed(3); // "42.000"

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function reverse(str) {
	var strReversed = '';
	for (let i = str.length - 1; i >= 0; i--) {
		strReversed += str.charAt(i);
    }
	return strReversed;
}
reverse('foo 𝌆 bar'); // rab �� oof
reverse('mañana mañana'); // anãnam anañam
// Use the package like Esrever to handle such things.

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var a = [];
a[2] = 1;
a.length; // 3
a; // [undefined, undefined, 1]

// You can set the key value pair to the array, but it doesn't count in length
a.a = 12;
a; // [undefined, undefined, a, a: 12];
a.length; // 3
a.a; // 12