Leetcode 473 Solution

This article provides solution to leetcode question 473 (matchsticks-to-square)
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https://leetcode.com/problems/matchsticks-to-square

Solution

class Solution {
public:
    bool makesquare(vector<int>& nums, vector<int>& sums, int i, int target)
    {
        if (sums[0] == target && sums[1] == target && sums[2] == target)
            return true;

        if (i == nums.size())
            return false;

        for (int j = 0; j < sums.size(); j++)
        {
            if (sums[j] + nums[i] <= target)
            {
                sums[j] += nums[i];
                if (makesquare(nums, sums, i + 1, target))
                    return true;
                sums[j] -= nums[i];
            }
        }

        return false;
    }

    bool makesquare(vector<int>& nums) {
        int s = accumulate(nums.begin(), nums.end(), 0);

        if (s % 4 || s == 0)
            return false;

        vector<int> sums(4);
        sort(nums.begin(), nums.end(), greater<int>());

        sums[0] = nums[0];

        return makesquare(nums, sums, 1, s / 4);
    }
};