Question

2248. Intersection of Multiple Arrays

中文文档

Description

Given a 2D integer array nums where nums[i] is a non-empty array of distinct positive integers, return _the list of integers that are present in each array of_ nums_ sorted in ascending order_.

 

Example 1:

Input: nums = [[3,1,2,4,5],[1,2,3,4],[3,4,5,6]]
Output: [3,4]
Explanation: 
The only integers present in each of nums[0] = [3,1,2,4,5], nums[1] = [1,2,3,4], and nums[2] = [3,4,5,6] are 3 and 4, so we return [3,4].

Example 2:

Input: nums = [[1,2,3],[4,5,6]]
Output: []
Explanation: 
There does not exist any integer present both in nums[0] and nums[1], so we return an empty list [].

 

Constraints:

• 1 <= nums.length <= 1000
• 1 <= sum(nums[i].length) <= 1000
• 1 <= nums[i][j] <= 1000
• All the values of nums[i] are unique.

Solutions

Solution 1

class Solution:
  def intersection(self, nums: List[List[int]]) -> List[int]:
    cnt = [0] * 1001
    for arr in nums:
      for x in arr:
        cnt[x] += 1
    return [x for x, v in enumerate(cnt) if v == len(nums)]

class Solution {
  public List<Integer> intersection(int[][] nums) {
    int[] cnt = new int[1001];
    for (var arr : nums) {
      for (int x : arr) {
        ++cnt[x];
      }
    }
    List<Integer> ans = new ArrayList<>();
    for (int x = 0; x < 1001; ++x) {
      if (cnt[x] == nums.length) {
        ans.add(x);
      }
    }
    return ans;
  }
}

class Solution {
public:
  vector<int> intersection(vector<vector<int>>& nums) {
    int cnt[1001]{};
    for (auto& arr : nums) {
      for (int& x : arr) {
        ++cnt[x];
      }
    }
    vector<int> ans;
    for (int x = 0; x < 1001; ++x) {
      if (cnt[x] == nums.size()) {
        ans.push_back(x);
      }
    }
    return ans;
  }
};

func intersection(nums [][]int) (ans []int) {
  cnt := [1001]int{}
  for _, arr := range nums {
    for _, x := range arr {
      cnt[x]++
    }
  }
  for x, v := range cnt {
    if v == len(nums) {
      ans = append(ans, x)
    }
  }
  return
}

function intersection(nums: number[][]): number[] {
  const cnt = new Array(1001).fill(0);
  for (const arr of nums) {
    for (const x of arr) {
      cnt[x]++;
    }
  }
  const ans: number[] = [];
  for (let x = 0; x < 1001; x++) {
    if (cnt[x] === nums.length) {
      ans.push(x);
    }
  }
  return ans;
}

class Solution {
  /**
   * @param Integer[][] $nums
   * @return Integer[]
   */
  function intersection($nums) {
    $rs = [];
    for ($i = 0; $i < count($nums); $i++) {
      for ($j = 0; $j < count($nums[$i]); $j++) {
        $hashtable[$nums[$i][$j]] += 1;
        if ($hashtable[$nums[$i][$j]] === count($nums)) {
          array_push($rs, $nums[$i][$j]);
        }
      }
    }
    sort($rs);
    return $rs;
  }
}

Solution 2

class Solution:
  def intersection(self, nums: List[List[int]]) -> List[int]:
    cnt = Counter()
    ans = []
    for arr in nums:
      for x in arr:
        cnt[x] += 1
        if cnt[x] == len(nums):
          ans.append(x)
    ans.sort()
    return ans

class Solution {
  public List<Integer> intersection(int[][] nums) {
    Map<Integer, Integer> cnt = new HashMap<>();
    List<Integer> ans = new ArrayList<>();
    for (var arr : nums) {
      for (int x : arr) {
        if (cnt.merge(x, 1, Integer::sum) == nums.length) {
          ans.add(x);
        }
      }
    }
    Collections.sort(ans);
    return ans;
  }
}

class Solution {
public:
  vector<int> intersection(vector<vector<int>>& nums) {
    unordered_map<int, int> cnt;
    vector<int> ans;
    for (auto& arr : nums) {
      for (int& x : arr) {
        if (++cnt[x] == nums.size()) {
          ans.push_back(x);
        }
      }
    }
    sort(ans.begin(), ans.end());
    return ans;
  }
};

func intersection(nums [][]int) (ans []int) {
  cnt := map[int]int{}
  for _, arr := range nums {
    for _, x := range arr {
      cnt[x]++
      if cnt[x] == len(nums) {
        ans = append(ans, x)
      }
    }
  }
  sort.Ints(ans)
  return
}

function intersection(nums: number[][]): number[] {
  const cnt = new Array(1001).fill(0);
  const ans: number[] = [];
  for (const arr of nums) {
    for (const x of arr) {
      if (++cnt[x] == nums.length) {
        ans.push(x);
      }
    }
  }
  ans.sort((a, b) => a - b);
  return ans;
}