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3132. Find the Integer Added to Array II

Description

You are given two integer arrays nums1 and nums2.

From nums1 two elements have been removed, and all other elements have been increased (or decreased in the case of negative) by an integer, represented by the variable x.

As a result, nums1 becomes equal to nums2. Two arrays are considered equal when they contain the same integers with the same frequencies.

Return the minimum possible integer x that achieves this equivalence.

 

Example 1:

Input: nums1 = [4,20,16,12,8], nums2 = [14,18,10]

Output: -2

Explanation:

After removing elements at indices [0,4] and adding -2, nums1 becomes [18,14,10].

Example 2:

Input: nums1 = [3,5,5,3], nums2 = [7,7]

Output: 2

Explanation:

After removing elements at indices [0,3] and adding 2, nums1 becomes [7,7].

 

Constraints:

  • 3 <= nums1.length <= 200
  • nums2.length == nums1.length - 2
  • 0 <= nums1[i], nums2[i] <= 1000
  • The test cases are generated in a way that there is an integer x such that nums1 can become equal to nums2 by removing two elements and adding x to each element of nums1.

Solutions

Solution 1: Sorting + Enumeration + Two Pointers

First, we sort the arrays $nums1$ and $nums2$. Since we need to remove two elements from $nums1$, we only need to consider the first three elements of $nums1$, denoted as $a_1, a_2, a_3$. We can enumerate the first element $b_1$ of $nums2$, then we can get $x = b_1 - a_i$, where $i \in {1, 2, 3}$. Then we can use the two pointers method to determine whether there exists an integer $x$ that makes $nums1$ and $nums2$ equal, and take the smallest $x$ that satisfies the condition.

The time complexity is $O(n \times \log n)$, and the space complexity is $O(\log n)$. Where $n$ is the length of the array.

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class Solution:
    def minimumAddedInteger(self, nums1: List[int], nums2: List[int]) -> int:
        def f(x: int) -> bool:
            i = j = cnt = 0
            while i < len(nums1) and j < len(nums2):
                if nums2[j] - nums1[i] != x:
                    cnt += 1
                else:
                    j += 1
                i += 1
            return cnt <= 2

        nums1.sort()
        nums2.sort()
        return min(
            x
            for x in (nums2[0] - nums1[0], nums2[0] - nums1[1], nums2[0] - nums1[2])
            if f(x)
        )

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class Solution {
    public int minimumAddedInteger(int[] nums1, int[] nums2) {
        Arrays.sort(nums1);
        Arrays.sort(nums2);
        int ans = 1 << 30;
        for (int i = 0; i < 3; ++i) {
            int x = nums2[0] - nums1[i];
            if (f(nums1, nums2, x)) {
                ans = Math.min(ans, x);
            }
        }
        return ans;
    }

    private boolean f(int[] nums1, int[] nums2, int x) {
        int i = 0, j = 0, cnt = 0;
        while (i < nums1.length && j < nums2.length) {
            if (nums2[j] - nums1[i] != x) {
                ++cnt;
            } else {
                ++j;
            }
            ++i;
        }
        return cnt <= 2;
    }
}

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class Solution {
public:
    int minimumAddedInteger(vector<int>& nums1, vector<int>& nums2) {
        sort(nums1.begin(), nums1.end());
        sort(nums2.begin(), nums2.end());
        int ans = 1 << 30;
        auto f = [&](int x) {
            int i = 0, j = 0, cnt = 0;
            while (i < nums1.size() && j < nums2.size()) {
                if (nums2[j] - nums1[i] != x) {
                    ++cnt;
                } else {
                    ++j;
                }
                ++i;
            }
            return cnt <= 2;
        };
        for (int i = 0; i < 3; ++i) {
            int x = nums2[0] - nums1[i];
            if (f(x)) {
                ans = min(ans, x);
            }
        }
        return ans;
    }
};

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func minimumAddedInteger(nums1 []int, nums2 []int) int {
    sort.Ints(nums1)
    sort.Ints(nums2)
    ans := 1 << 30
    f := func(x int) bool {
        i, j, cnt := 0, 0, 0
        for i < len(nums1) && j < len(nums2) {
            if nums2[j]-nums1[i] != x {
                cnt++
            } else {
                j++
            }
            i++
        }
        return cnt <= 2
    }
    for _, a := range nums1[:3] {
        x := nums2[0] - a
        if f(x) {
            ans = min(ans, x)
        }
    }
    return ans
}

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function minimumAddedInteger(nums1: number[], nums2: number[]): number {
    nums1.sort((a, b) => a - b);
    nums2.sort((a, b) => a - b);
    const f = (x: number): boolean => {
        let [i, j, cnt] = [0, 0, 0];
        while (i < nums1.length && j < nums2.length) {
            if (nums2[j] - nums1[i] !== x) {
                ++cnt;
            } else {
                ++j;
            }
            ++i;
        }
        return cnt <= 2;
    };
    let ans = Infinity;
    for (let i = 0; i < 3; ++i) {
        const x = nums2[0] - nums1[i];
        if (f(x)) {
            ans = Math.min(ans, x);
        }
    }
    return ans;
}

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