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Monotonic Array

Nov 19, 2022CodeCatch
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format duration

Nov 19, 2022CodeCatch

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const formatDuration = ms => {
if (ms < 0) ms = -ms;
const time = {
day: Math.floor(ms / 86400000),
hour: Math.floor(ms / 3600000) % 24,
minute: Math.floor(ms / 60000) % 60,
second: Math.floor(ms / 1000) % 60,
millisecond: Math.floor(ms) % 1000
};
return Object.entries(time)
.filter(val => val[1] !== 0)
.map(([key, val]) => `${val} ${key}${val !== 1 ? 's' : ''}`)
.join(', ');
};
formatDuration(1001); // '1 second, 1 millisecond'
formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds'

graph example

Nov 19, 2022CodeCatch

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class Graph {
constructor(directed = true) {
this.directed = directed;
this.nodes = [];
this.edges = new Map();
}
addNode(key, value = key) {
this.nodes.push({ key, value });
}
addEdge(a, b, weight) {
this.edges.set(JSON.stringify([a, b]), { a, b, weight });
if (!this.directed)
this.edges.set(JSON.stringify([b, a]), { a: b, b: a, weight });
}
removeNode(key) {
this.nodes = this.nodes.filter(n => n.key !== key);
[...this.edges.values()].forEach(({ a, b }) => {
if (a === key || b === key) this.edges.delete(JSON.stringify([a, b]));
});
}
removeEdge(a, b) {
this.edges.delete(JSON.stringify([a, b]));
if (!this.directed) this.edges.delete(JSON.stringify([b, a]));
}
findNode(key) {
return this.nodes.find(x => x.key === key);
}
hasEdge(a, b) {
return this.edges.has(JSON.stringify([a, b]));
}
setEdgeWeight(a, b, weight) {
this.edges.set(JSON.stringify([a, b]), { a, b, weight });
if (!this.directed)
this.edges.set(JSON.stringify([b, a]), { a: b, b: a, weight });
}
getEdgeWeight(a, b) {
return this.edges.get(JSON.stringify([a, b])).weight;
}
adjacent(key) {
return [...this.edges.values()].reduce((acc, { a, b }) => {
if (a === key) acc.push(b);
return acc;
}, []);
}
indegree(key) {
return [...this.edges.values()].reduce((acc, { a, b }) => {
if (b === key) acc++;
return acc;
}, 0);
}
outdegree(key) {
return [...this.edges.values()].reduce((acc, { a, b }) => {
if (a === key) acc++;
return acc;
}, 0);
}
}
const g = new Graph();
g.addNode('a');
g.addNode('b');
g.addNode('c');
g.addNode('d');
g.addEdge('a', 'c');
g.addEdge('b', 'c');
g.addEdge('c', 'b');
g.addEdge('d', 'a');
g.nodes.map(x => x.value); // ['a', 'b', 'c', 'd']
[...g.edges.values()].map(({ a, b }) => `${a} => ${b}`);
// ['a => c', 'b => c', 'c => b', 'd => a']
g.adjacent('c'); // ['b']
g.indegree('c'); // 2
g.outdegree('c'); // 1
g.hasEdge('d', 'a'); // true
g.hasEdge('a', 'd'); // false
g.removeEdge('c', 'b');
[...g.edges.values()].map(({ a, b }) => `${a} => ${b}`);
// ['a => c', 'b => c', 'd => a']
g.removeNode('c');
g.nodes.map(x => x.value); // ['a', 'b', 'd']
[...g.edges.values()].map(({ a, b }) => `${a} => ${b}`);
// ['d => a']
g.setEdgeWeight('d', 'a', 5);
g.getEdgeWeight('d', 'a'); // 5

Date Time Testing

Nov 18, 2022AustinLeath

0 likes • 2 views

var d = new Date();
var d = new Date(milliseconds);
var d = new Date(dateString);
var d = new Date(year, month, day, hours, minutes, seconds, milliseconds);

levenshtein distance

Nov 19, 2022CodeCatch

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const levenshteinDistance = (s, t) => {
if (!s.length) return t.length;
if (!t.length) return s.length;
const arr = [];
for (let i = 0; i <= t.length; i++) {
arr[i] = [i];
for (let j = 1; j <= s.length; j++) {
arr[i][j] =
i === 0
? j
: Math.min(
arr[i - 1][j] + 1,
arr[i][j - 1] + 1,
arr[i - 1][j - 1] + (s[j - 1] === t[i - 1] ? 0 : 1)
);
}
}
return arr[t.length][s.length];
};
levenshteinDistance('duck', 'dark'); // 2

Redux Slice

Mar 11, 2021C S

1 like • 0 views

import { createSlice } from "@reduxjs/toolkit";
const alert = createSlice({
name: "alert",
initialState: {
msg: "",
status: "",
},
reducers: {
set_alert: (state, action) => {
return {
...state,
msg: action.payload.msg,
status: action.payload.status,
};
},
clear_alert: (state, action) => {
return {
...state,
msg: "",
status: "",
};
},
},
});
export default alert.reducer;
const { set_alert, clear_alert } = alert.actions;
export const setAlert = (msg, status) => dispatch => {
dispatch(set_alert({ msg, status }));
setTimeout(() => dispatch(clear_alert()), 4000);
};
export const clearAlert = () => dispatch => {
dispatch(clear_alert());
};

unzipWith() function

Nov 19, 2022CodeCatch

0 likes • 0 views

const unzipWith = (arr, fn) =>
arr
.reduce(
(acc, val) => (val.forEach((v, i) => acc[i].push(v)), acc),
Array.from({
length: Math.max(...arr.map(x => x.length))
}).map(x => [])
)
.map(val => fn(...val));
unzipWith(
[
[1, 10, 100],
[2, 20, 200],
],
(...args) => args.reduce((acc, v) => acc + v, 0)
);
// [3, 30, 300]