 Balancing longest balanced sequence array with javascript | Sololearn: Learn to code for FREE!

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# Balancing longest balanced sequence array with javascript

How to balance and array the code like input 1,2,-2,-1,3,4,-3 the output is 4 because 1,2,-2,-1 is balance one rather than 3,4,-3 You must open parentheses must be closed by the same type of parentheses. this is my code : var ans, s, temp, n, a; n = 7; a = 1,2,-2,-1,3,4,-3; s = []; ans = 0; for (var i = 0, a = n; i < a.length; i += 1) { if (a[i] > 0) { s.append(i); } else { if (a[i] < 0) { if (s && a[i] === -a[s.slice(-1)]) { s.pop(); if (!s) { temp = -1; } else { temp = s.slice(-1); } ans = max(ans, i - temp); } else { s.append(i); } } } } console.log(ans); please teach me with hard ways not simple ways if can Thank You

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Please try this: const BalanceSeq = arr => { let Seq = []; for(let i = 0; i < arr.length; i++) { if(arr[i]==-arr[i+1]){ for(let a = 0; a < arr.length/2+1; a++) { if(arr[i-a]!=-arr[i+1+a]) { Seq = arr.slice(i-a+1,i+a+1); break } } } } return `Array: [\${Seq}] - Length: \${Seq.length}\n`; } console.log(BalanceSeq([1,2,-2,-1,3,4,-3])) console.log(BalanceSeq([7,5,5,1,2,-2,-1,-5,3,4,-3])) console.log(BalanceSeq([3,-4,1,2,-2,-1,3,4])) console.log(BalanceSeq([2,3,2,-8,1,3,-3,-1,8,-2,-3,4,1])) https://code.sololearn.com/WtAIo8flOYXl/?ref=app

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if(arr[i]==-arr[i+1]) for finding the center of sequence (like 2,-2 is center)

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Jansen Su I edited my code for must be start by positive (re cheak please)

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let x = [1,2,-2,-1,3,4,-3]; console.log(x.reduce((a,b)=> a+b, 0))

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@Ipang, the balanced sequence is like 1 2 -2 -1 = balanced sequence that's why the output is 4 because the balance subarray has 4 numbers. If you do like 1 2 -1 -2 this is not balanced. You must have open parentheses must be closed by the same type of parentheses.

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@SAN if(arr[i]==-arr[i+1]) what is this statement mean? for(let a = 0; a < arr.length/2+1; a++) { at this statement why is the arr.length/2+1 like this? if(arr[i-a]!=-arr[i+1+a]) { Seq = arr.slice(i-a+1,i+a+1); break } what does this statement do for the case I know this is for placement and checking the balance but how to explain properly about this statement? return `Array: [\${Seq}] - Length: \${Seq.length}\n`; what is this mean? Thank you for the help, I need to understand this more for more experience

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@Ipang 1, 2, -2, -1 // longest balanced sub sequence

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What was the criteria for a balanced sequence here? is it cause the sequence result in zero? as in 1 + 2 + (-2) + (-1) or is it cause the sequence is palindromic, disregarding sign?

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Thanks Jansen Su I get it now So your goal was to find the longest balanced sequence or to balance a given sequence. The post's title seem to be asking for how to balance the sequence ...

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Yes, I need to learn the way how to implement it without any simple solution, so I can learn about it more

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@SAN I get it now So after we get the middle, this code now on going for(let a = 0; a < arr.length/2+1; a++) { if(arr[i-a]!=-arr[i+1+a]) { Seq = arr.slice(i-a+1,i+a+1); break why must arr.length/2+1? and the if is the checker if the one we check is not balanced like the other we remove the number, right?

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Jansen Su I'm still unclear whether you want to find the longest balanced sub sequence 1, 2, -2, -1 // longest balanced sub sequence Or make the entire array balanced 1, 2, -2, -1, -2, 2, 1 // modify last 3

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@SAN if the case for this one console.log(BalanceSeq([2,3,2,-8,1,3,-3,-1,8,-2,-3,4,1])) so I want the case to be like balanced sub sequence must be positive first then negative close so for that result should be 1,3,-3,-1 from your code how to change that to be only open positive and closing negative?