### Positive Prefixes Codechef December long challenge solution | Codechef December long challeng editorial

## Problem Statement -

this Problem Positive prefix taken from CodeChef December long challenge.Let's read Problem statement.

You are given two positive integers and , where . Find a sequence such that:

- for each valid , is either or
- there are exactly values of such that and

If there are multiple solutions, you may print any one of them. It can be proved that at least one solution always exists.

### Input

- The first line of the input contains a single integer denoting the number of test cases. The description of test cases follows.
- The first and only line of each test case contains two space-separated integers and .

### Output

For each test case, print a single line containing space-separated integers .

### Constraints

### Subtasks

Subtask #1 (10 points):

Subtask #2 (90 points): original constraints

### Example Input

```
1
3 3
```

### Example Output

`1 2 3`

### Solution-

Hint- learn Prefix array to solve this question.

This question is totally observation-based.You should good observer to solve this problem.

Solution since there can be multiple solution of this problem one of them is to print alternate +i and -i.

in my case what i am doing

I have created an output array in which i am storing +i and -i alternatively.

then I iterate over the array and I calculate the prefix array.

Then I calculated total positive and negative number store in the output array.And i build the following logic

if(k<=positive){

int diff=positive-k;

for(int i=n;i>0&&diff>0;i--){

if(prefix[i]>0){

output[i]=-output[i];

diff--;

}

}

}

else{

int diff=k-positive;

for(int i=n;i>0&&diff>0;i--){

if(prefix[i]<0){

output[i]=-output[i];

diff--;

}

}

}

Here is my entire code.

Join Telegram Channel for solution.

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