Generate Random elements without duplicate
I am trying to make a Random Number Generator.
I made a code and it does work well.
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const arr = ;
if(min >= max) return;
if(max - min + 1 < count) return;
while (arr.length < count) {
let num = Math.floor(Math.random() * max) + min;
let flag = arr.every((i) => {
return i === num ? false : true;
});
if (flag) {
arr.push(num);
}
}
console.log(arr);
}<button id="btn">Gen</button>But my algorithm's time complexity is O(n). (I am not sure, I didn't calculate it strictly)
I hope to reduce the time complexity if I can.
And, I guess my above code can be compacted, but I can't.
Summary What I Want
To reduce the time complexity if it can be
To make it compacted
javascript random
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
add a comment |
I am trying to make a Random Number Generator.
I made a code and it does work well.
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const arr = ;
if(min >= max) return;
if(max - min + 1 < count) return;
while (arr.length < count) {
let num = Math.floor(Math.random() * max) + min;
let flag = arr.every((i) => {
return i === num ? false : true;
});
if (flag) {
arr.push(num);
}
}
console.log(arr);
}<button id="btn">Gen</button>But my algorithm's time complexity is O(n). (I am not sure, I didn't calculate it strictly)
I hope to reduce the time complexity if I can.
And, I guess my above code can be compacted, but I can't.
Summary What I Want
To reduce the time complexity if it can be
To make it compacted
javascript random
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
add a comment |
I am trying to make a Random Number Generator.
I made a code and it does work well.
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const arr = ;
if(min >= max) return;
if(max - min + 1 < count) return;
while (arr.length < count) {
let num = Math.floor(Math.random() * max) + min;
let flag = arr.every((i) => {
return i === num ? false : true;
});
if (flag) {
arr.push(num);
}
}
console.log(arr);
}<button id="btn">Gen</button>But my algorithm's time complexity is O(n). (I am not sure, I didn't calculate it strictly)
I hope to reduce the time complexity if I can.
And, I guess my above code can be compacted, but I can't.
Summary What I Want
To reduce the time complexity if it can be
To make it compacted
javascript random
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
I am trying to make a Random Number Generator.
I made a code and it does work well.
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const arr = ;
if(min >= max) return;
if(max - min + 1 < count) return;
while (arr.length < count) {
let num = Math.floor(Math.random() * max) + min;
let flag = arr.every((i) => {
return i === num ? false : true;
});
if (flag) {
arr.push(num);
}
}
console.log(arr);
}<button id="btn">Gen</button>But my algorithm's time complexity is O(n). (I am not sure, I didn't calculate it strictly)
I hope to reduce the time complexity if I can.
And, I guess my above code can be compacted, but I can't.
Summary What I Want
To reduce the time complexity if it can be
To make it compacted
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const arr = ;
if(min >= max) return;
if(max - min + 1 < count) return;
while (arr.length < count) {
let num = Math.floor(Math.random() * max) + min;
let flag = arr.every((i) => {
return i === num ? false : true;
});
if (flag) {
arr.push(num);
}
}
console.log(arr);
}<button id="btn">Gen</button>document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const arr = ;
if(min >= max) return;
if(max - min + 1 < count) return;
while (arr.length < count) {
let num = Math.floor(Math.random() * max) + min;
let flag = arr.every((i) => {
return i === num ? false : true;
});
if (flag) {
arr.push(num);
}
}
console.log(arr);
}<button id="btn">Gen</button>javascript random
javascript random
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
edited Nov 24 '18 at 16:57
zynkn
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
asked Nov 24 '18 at 16:45
zynknzynkn
3,92321030
3,92321030
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
You can use a Set (which will take care of duplicates) instead of an array and keep checking its size until you have all the numbers you want:
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>answered Nov 24 '18 at 16:48
sliderslider
8,37311130
1
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can use a Set (which will take care of duplicates) instead of an array and keep checking its size until you have all the numbers you want:
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>answered Nov 24 '18 at 16:48
sliderslider
8,37311130
1
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
add a comment |
You can use a Set (which will take care of duplicates) instead of an array and keep checking its size until you have all the numbers you want:
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>answered Nov 24 '18 at 16:48
sliderslider
8,37311130
1
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
add a comment |
You can use a Set (which will take care of duplicates) instead of an array and keep checking its size until you have all the numbers you want:
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>answered Nov 24 '18 at 16:48
sliderslider
8,37311130
You can use a Set (which will take care of duplicates) instead of an array and keep checking its size until you have all the numbers you want:
document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>document.querySelector('#btn').addEventListener('click',()=>{
generate(1,45,6)
});
function generate(min, max, count){
const s = new Set();
if(min >= max) return;
if(max - min + 1 < count) return;
while (s.size < count) { // O(1)
let num = Math.floor(Math.random() * max) + min;
s.add(num); // O(1)
}
console.log(Array.from(s));
}<button id="btn">Gen</button>answered Nov 24 '18 at 16:48
sliderslider
8,37311130
answered Nov 24 '18 at 16:48
sliderslider
8,37311130
answered Nov 24 '18 at 16:48
sliderslider
8,37311130
answered Nov 24 '18 at 16:48
sliderslider
8,37311130
8,37311130
1
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
add a comment |
1
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
1
1
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
This is exactly what I was looking for!
– zynkn
Nov 24 '18 at 16:51
add a comment |
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