TheAlgorithms/Go · error

ErrInvalidPosition

ErrInvalidPosition

Error message

invalid position in subset

What it means

Inside the subset-sum DP loop, index j-array[i-1] would fall outside the subset table (negative or beyond sum) for the current element, so IsSubsetSum bails out with ErrInvalidPosition instead of indexing out of bounds — typically caused by array elements larger than the target sum.

Source

Thrown at dynamic/subsetsum.go:12

//Given a set of non-negative integers, and a (positive) value sum,
//determine if there is a subset of the given set with sum
//equal to given sum.
// time complexity: O(n*sum)
// space complexity: O(n*sum)
//references: https://www.geeksforgeeks.org/subset-sum-problem-dp-25/

package dynamic

import "fmt"

var ErrInvalidPosition = fmt.Errorf("invalid position in subset")
var ErrNegativeSum = fmt.Errorf("negative sum is not allowed")

func IsSubsetSum(array []int, sum int) (bool, error) {
	if sum < 0 {
		//not allow negative sum
		return false, ErrNegativeSum
	}

	//create subset matrix
	arraySize := len(array)
	subset := make([][]bool, arraySize+1)
	for i := 0; i <= arraySize; i++ {
		subset[i] = make([]bool, sum+1)
	}

	for i := 0; i <= arraySize; i++ {
		//sum 0 is always true
		subset[i][0] = true

View on GitHub (pinned to 5ba447ec5f)

Solutions

1. Filter array elements greater than sum before calling IsSubsetSum
2. Guard the index computation (j-array[i-1]) before table access
3. Handle via errors.Is(err, ErrInvalidPosition) and sanitize the input set

When it happens

Trigger: Thrown at dynamic/subsetsum.go:12 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of TheAlgorithms/Go@5ba447ec5f (2026-09-02). Data as JSON: /api/errors/10ffd5ac3fba1b63. Report an issue: GitHub.