The resultArr returned by the combinationSum function is empty. When I console log the ds array, it prints the correct answer, but the final output array is [[],[]].
var combinationSum = function(candidates, target) {
const resultArr = []
function combinationSumHelper(idx, candidates, ds, target){
if(idx === candidates.length){ // base case
if(target === 0){
console.log(ds) *// This line outputs right ans but resultArr returned by combinationSum function is empty*
resultArr.push(ds)
}
return
}
if(candidates[idx] <= target){
ds.push(candidates[idx])
combinationSumHelper(idx, candidates, ds, target - candidates[idx])
ds.pop()
}
combinationSumHelper(idx+1, candidates, ds, target)
}
combinationSumHelper(0, candidates, [], target)
return resultArr
};
console.log(combinationSum([2,3,6,7], 7))
OUTPUT: [ [], [] ]
EXPECTED OUTPUT: [[2,2,3],[7]]
STDOUT: [ 2, 2, 3 ] [ 7 ]
This will give you the output you are looking for:
var combinationSum = function(candidates, target) {
const resultArr = []
function combinationSumHelper(idx, candidates, ds, target){
if(idx === candidates.length){ // base case
if(target === 0){
console.log(ds) *// This line outputs right ans but resultArr returned by combinationSum function is empty*
resultArr.push([...ds])
}
return
}
if(candidates[idx] <= target){
ds.push(candidates[idx])
combinationSumHelper(idx, candidates, ds, target - candidates[idx])
ds.pop()
}
combinationSumHelper(idx+1, candidates, ds, target)
}
combinationSumHelper(0, candidates, [], target)
return resultArr
};
console.log(combinationSum([2,3,6,7], 7))
The problem you are facing is the below if
clause with ds.push
and ds.pop
is mutating your array and the final output.
By changing your code to resultArr.push([...ds])
, you can make a copy of your array. This will ensure it will not get mutated further on.
When I run this code the output I get is: [[2, 2, 3], [7]]