solution.cpp

#include <vector>
#include <unordered_map>
using namespace std;

class Solution
{
public:
    int minSubarray(vector<int> &nums, int p)
    {
        long totalSum = 0;
        for (int num : nums)
        {
            totalSum += num;
        }

        // Find the remainder when total sum is divided by p
        int rem = totalSum % p;
        if (rem == 0)
            return 0; // If the remainder is 0, no subarray needs to be removed

        unordered_map<int, int> prefixMod;
        prefixMod[0] = -1; // Initialize for handling full prefix
        long prefixSum = 0;
        int minLength = nums.size();

        for (int i = 0; i < nums.size(); ++i)
        {
            prefixSum += nums[i];
            int currentMod = prefixSum % p;
            int targetMod = (currentMod - rem + p) % p;

            if (prefixMod.find(targetMod) != prefixMod.end())
            {
                minLength = min(minLength, i - prefixMod[targetMod]);
            }

            prefixMod[currentMod] = i;
        }

        return minLength == nums.size() ? -1 : minLength;
    }
};