lyleaf’s gists

lyleaf / 210. Course Schedule II.cpp

Last active August 19, 2016 05:23

Topological Sort Using BFS/DFS

	/*
	我的naive方法如下。大体上是正确的BFS，就是每一次找出没有入的节点，放到答案的vector里面去。
	如何找出没有入的节点呢？我用的是每一次都用一个新的数组prerequisites来看。每一次就把prerequisites中已经放入vector的course的约束删除。但这
	样每一回都要新建一个prerequisites vector.
	为什么不直接用一个degree来标志入节点的个数呢？
	*/


	class Solution {
	public:

lyleaf / 23. Merge k Sorted Lists.cpp

Last active August 22, 2016 08:01

把k个已经sort了的linked list合并成一个linked list. key words: priority_queue

	/**
	* Definition for singly-linked list.
	* struct ListNode {
	* int val;
	* ListNode *next;
	* ListNode(int x) : val(x), next(NULL) {}
	* };
	*/
	class Solution {
	public:

lyleaf / 2. Add Two Numbers.cpp

Last active August 23, 2016 07:47

两个整数分别用两个Linked List 表示，把它们加起来

	class Solution {
	public:
	ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
	int before = 0;
	ListNode* res = new ListNode(0);
	ListNode* pre = res;
	while (l1 != NULL \|\| l2 != NULL){
	int current = 0;
	if (!l2) { current = l1->val; l1 = l1->next; }
	else if (!l1) { current = l2->val; l2 = l2->next; }

lyleaf / 16. 3Sum Closest.cpp

Created August 23, 2016 11:52

一个vector里3个数加在一起离target最近的值。Two Pointers

	class Solution {
	public:
	int threeSumClosest(vector<int>& nums, int target) {
	int res = target + 1000;
	sort(nums.begin(),nums.end());
	for (int i=0;i<nums.size()-2;i++){
	int target2 = target - nums[i];
	int j=i+1;
	int k=nums.size()-1;
	while (j<k){

lyleaf / 117. Populating Next Right Pointers in Each Node II.cpp

Last active August 23, 2016 13:23

	/**
	我的方法用了一个queue,再用一个NULL指针来分辨是不是一层的。
	看了答案以后发现optimized的解法是，不需要用queue，因为这个next的link已经可以serve as queue.

	* Definition for binary tree with next pointer.
	* struct TreeLinkNode {
	* int val;
	* TreeLinkNode left, right, *next;
	* TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
	* };

lyleaf / 26. Remove Duplicates from Sorted Array.cpp

Last active August 24, 2016 18:20

sorted array去重只需要O(n) time, O(1) space

-class Solution {
-public:
-    int removeDuplicates(vector<int>& nums) {
-        if (nums.empty()) return 0;
-        int cur = 0;
-        for (int i=1;i<nums.size();i++){
-            if (nums[i] != nums[cur]){
-                swap(nums[i],nums[++cur]);
-            }
-        }

lyleaf / loop.js

Created September 30, 2019 03:49

Loop an array asynchronously with map

	exports.getTranslations = functions.https.onRequest(async (req, res) => {
	const english_words = req.body.english_words \|\| [];
	console.log(english_words);
	const collectionRef = admin.firestore().collection("translations");
	const createResponse = (res) => {
	var data = {
	english_word: (res === undefined) ? '' : res.english_word ,
	translation: (res === undefined) ? '' : res.translation ,
	transliteration: (res === undefined) ? '' : res.transliteration,
	sound_link: (res === undefined) ? '' : res.sound_link

lyleaf / shape2geojson.py

Last active October 2, 2019 06:14

Create geojson from shape file

	import shapefile
	# read the shapefile

	reader = shapefile.Reader("hello.shp")
	fields = reader.fields[1:]
	field_names = [field[0] for field in fields]
	buffer = []
	for sr in reader.shapeRecords():
	atr = dict(zip(field_names, sr.record))
	geom = sr.shape.__geo_interface__

lyleaf / geojson2bigquery.py

Created October 2, 2019 06:10

Convert geojson to get schema to upload to bigquery

	import json
	with open('HGURiau_EoF2019ATR2014Bappenas2011.json', 'r') as ifp:
	with open('to_load.json', 'w') as ofp:
	features = json.load(ifp)['features']
	print(features)
	# new-line-separated JSON
	schema = None
	for obj in features:
	props = obj['properties'] # a dictionary
	props['geometry'] = json.dumps(obj['geometry']) # make the geometry a string

lyleaf / pyaudio_recorder.py

Created November 10, 2019 07:14

pyaudio_recorder.py

	import pyaudio
	import wave

	sample_format = pyaudio.paFloat32 # 16 bits per sample
	channels = 1
	fs = 44100 # Record at 44100 samples per second
	seconds = 10
	filename = "output.wav"
	chunk = 2048#fs*5 # Record in chunks of 1024 samples

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