how can I determine when the first X numbers of an array is in order AND the last element in 0? i.e the array is
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0
I currently have this, but this relies on the array always being the same, which isn't very flexibile
const sorted = (array) => {
const solved = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0]
return (JSON.stringify(array) == JSON.stringify(solved))
}
First define a generic function to verify that a segment of an array is sorted, then define a second function that uses the first to see the first values are sorted, and add a check for the final value:
function isSegmentSorted(array, start=0, end=array.length) {
for (let i = start + 1; i < end; i++) {
if (array[i - 1] > array[i]) return false;
}
return true;
}
function isSortedWithExtraZero(array) {
return array.at(-1) === 0 &&
isSegmentSorted(array, 0, array.length - 1);
}
var array = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,0];
console.log(isSortedWithExtraZero(array));You could do something as simple as this:
const checkArray = (arr) => {
if(arr[arr.length-1] != 0){
return false;
}
const nums = arr.slice(0, arr.length - 1);
const sortedArr = [...nums].sort((a, b) => a - b);
for (let i = 0; i < nums.length; i++) {
if(nums[i] != sortedArr[i]){
return false;
}
}
return true;
}
console.log(checkArray([1,2,3,0])); // true
console.log(checkArray([1,2,3,4])); // false
console.log(checkArray([1,3,2,0])); // falseBasically the steps are:
In the end you return true only if every condition is verified.
This is generic enough so that if in the future you want to change the sorting type you can just act on the sort function (for example if you want to make it descending).
We can use every function for that. With !idx we exclude the first index 0, then we check if idx is less than the length of your array. If so, check if it is sorted, else check it it equals to zero.
const solutions = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0];
const sorted = solutions.every((val, idx, arr) =>
!idx || (idx < solutions.length - 1 ? arr[idx - 1] <= val : val === 0)
);
console.log(sorted);