TheAlgorithms/Java · error · IllegalArgumentException

Input array should not contain negative number(s).

Error message

Input array should not contain negative number(s).

What it means

Thrown by MinimumSumPartition.minimumSumPartition(int[]) when any array element is negative. The algorithm builds a subset-sum DP table indexed by sums; negative values would create invalid/negative array indices, so they are rejected up front via throwIfInvalidInput. The message is 'Input array should not contain negative number(s).'

Source

Thrown at src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java:28

Input:  array[] = {1, 6, 11, 4}
Output: 0
Explanation:
Subset1 = {1, 4, 6}, sum of Subset1 = 11
Subset2 = {11}, sum of Subset2 = 11

Input:  array[] = {36, 7, 46, 40}
Output: 23
Explanation:
Subset1 = {7, 46} ;  sum of Subset1 = 53
Subset2 = {36, 40} ; sum of Subset2  = 76
 */
public final class MinimumSumPartition {
    private MinimumSumPartition() {
    }

    private static void throwIfInvalidInput(final int[] array) {
        if (Arrays.stream(array).anyMatch(a -> a < 0)) {
            throw new IllegalArgumentException("Input array should not contain negative number(s).");
        }
    }

    public static int minimumSumPartition(final int[] array) {
        throwIfInvalidInput(array);
        int sum = Arrays.stream(array).sum();
        boolean[] dp = new boolean[sum / 2 + 1];
        dp[0] = true; // Base case , don't select any element from array

        // Find the closest sum of subset array that we can achieve which is closest to half of sum of full array
        int closestPartitionSum = 0;

        for (int i = 0; i < array.length; i++) {
            for (int j = sum / 2; j > 0; j--) {
                if (array[i] <= j) {
                    dp[j] = dp[j] || dp[j - array[i]];
                }
                if (dp[j]) {

View on GitHub (pinned to fdfb9a395b)

Solutions

1. Filter or reject negative values before calling minimumSumPartition (validate at the data boundary).
2. Convert the problem domain so weights are non-negative, or take absolute values only if semantically correct.
3. Add a unit test that asserts no negative slips through the input pipeline.

Example fix

// before
int result = MinimumSumPartition.minimumSumPartition(arr);

// after
for (int v : arr) {
    if (v < 0) throw new IllegalArgumentException("no negatives: " + v);
}
int result = MinimumSumPartition.minimumSumPartition(arr);

for (int v : array) {
    if (v < 0) throw new IllegalArgumentException("no negatives: " + v);
}
MinimumSumPartition.minimumSumPartition(array);

When it happens

Trigger: Passing an array containing a negative value; reading signed integers from external data without sanitizing; using a sentinel like -1 in the input.

Common situations: Mixing sentinel/error markers into real data; off-by-one when slicing arrays; numeric parsing that allows leading '-' signs.

Related errors

• Frequencies cannot be negative
• Keys and frequencies cannot be null
• Keys and frequencies must have the same length
• Price array cannot be null or empty.
• Rod length cannot be negative.

AI-assisted analysis of TheAlgorithms/Java@fdfb9a395b (2026-08-13). Data as JSON: /api/errors/6a0f600011acaff2. Report an issue: GitHub.