Currently, I am tackling some challenging Javascript problems on Code Signal and came across this particular question:
When presented with an array of integers in a sequence, can you determine if it is possible to create a strictly increasing sequence by removing no more than one element from the array?**
Note: A sequence a0, a1, ..., an is deemed strictly increasing if a0 < a1 < ... < an. Also, a sequence comprising only one element is considered strictly increasing as well.
For example, if we have a sequence = [1, 3, 2, 1], the output should be almostIncreasingSequence(sequence) = false.
The given array does not contain any single element that can be omitted to achieve a strictly increasing sequence. On the other hand, for a sequence like [1, 3, 2], the expected output is almostIncreasingSequence(sequence) = true.
In this case, removing the number 3 from the array results in the strictly increasing sequence [1, 2]. Alternatively, you could remove 2 to get [1, 3].
To solve this problem, my approach involves iterating through the sequence array to check if the current element exceeds the subsequent element. If so, the current element is removed. Then, a counter is incremented, and if the count is less than 2, return true; otherwise, return false.
Below is the code snippet:
function almostIncreasingSequence(sequence) {
// Return true if array has 1 or 2 elements
if(sequence.length <= 2) {
return true;
}
// Keep track of removed numbers
let numberRemoved = 0;
// Loop through array, compare current element with next
// If greater than next, increment numberRemoved and remove current element
for(let i = 0; i < sequence.length; i++) {
if(sequence[i] >= sequence[i + 1]) {
numberRemoved++;
// Remove element that's greater than next
let removed = sequence.splice([i], 1);
i = 0;
console.log(sequence);
}
}
for(let j = 0; j < sequence.length; j++) {
if(sequence[j] >= sequence[j + 1]) {
numberRemoved++;
}
}
// Pass if number of removals is less than 2
if(numberRemoved < 2) {
return true;
}
else {
return false;
}
}
This implementation solves most test cases except for two instances where handling edge cases becomes crucial. For example, when comparing sequence[i] and sequence[i + 1], removing sequence[i] at times may not give the desired result, and removing sequence[i + 1] might actually lead to success instead. How can this issue be resolved without resorting to a second loop through the array?