Welcome to Subscribe On Youtube

2094. Finding 3-Digit Even Numbers

Description

You are given an integer array digits, where each element is a digit. The array may contain duplicates.

You need to find all the unique integers that follow the given requirements:

• The integer consists of the concatenation of three elements from digits in any arbitrary order.
• The integer does not have leading zeros.
• The integer is even.

For example, if the given digits were [1, 2, 3], integers 132 and 312 follow the requirements.

Return a sorted array of the unique integers.

 

Example 1:

Input: digits = [2,1,3,0]
Output: [102,120,130,132,210,230,302,310,312,320]
Explanation: All the possible integers that follow the requirements are in the output array. 
Notice that there are no odd integers or integers with leading zeros.

Example 2:

Input: digits = [2,2,8,8,2]
Output: [222,228,282,288,822,828,882]
Explanation: The same digit can be used as many times as it appears in digits. 
In this example, the digit 8 is used twice each time in 288, 828, and 882. 

Example 3:

Input: digits = [3,7,5]
Output: []
Explanation: No even integers can be formed using the given digits.

 

Constraints:

• 3 <= digits.length <= 100
• 0 <= digits[i] <= 9

Solutions

• Java
• C++
• Python
• Go
• TypeScript
• Javascript

• class Solution {
      public int[] findEvenNumbers(int[] digits) {
          int[] counter = count(digits);
          List<Integer> ans = new ArrayList<>();
          for (int i = 100; i < 1000; i += 2) {
              int[] t = new int[3];
              for (int j = 0, k = i; k > 0; ++j) {
                  t[j] = k % 10;
                  k /= 10;
              }
              int[] cnt = count(t);
              if (check(counter, cnt)) {
                  ans.add(i);
              }
          }
          return ans.stream().mapToInt(Integer::valueOf).toArray();
      }
  
      private boolean check(int[] cnt1, int[] cnt2) {
          for (int i = 0; i < 10; ++i) {
              if (cnt1[i] < cnt2[i]) {
                  return false;
              }
          }
          return true;
      }
  
      private int[] count(int[] nums) {
          int[] counter = new int[10];
          for (int num : nums) {
              ++counter[num];
          }
          return counter;
      }
  }
  

• class Solution {
  public:
      vector<int> findEvenNumbers(vector<int>& digits) {
          vector<int> counter = count(digits);
          vector<int> ans;
          for (int i = 100; i < 1000; i += 2) {
              vector<int> t(3);
              for (int j = 0, k = i; k > 0; ++j) {
                  t[j] = k % 10;
                  k /= 10;
              }
              vector<int> cnt = count(t);
              if (check(counter, cnt)) ans.push_back(i);
          }
          return ans;
      }
  
      vector<int> count(vector<int>& nums) {
          vector<int> counter(10);
          for (int num : nums) ++counter[num];
          return counter;
      }
  
      bool check(vector<int>& cnt1, vector<int>& cnt2) {
          for (int i = 0; i < 10; ++i)
              if (cnt1[i] < cnt2[i])
                  return false;
          return true;
      }
  };
  

• class Solution:
      def findEvenNumbers(self, digits: List[int]) -> List[int]:
          ans = []
          counter = Counter(digits)
          for i in range(100, 1000, 2):
              t = []
              k = i
              while k:
                  t.append(k % 10)
                  k //= 10
              cnt = Counter(t)
              if all([counter[i] >= cnt[i] for i in range(10)]):
                  ans.append(i)
          return ans
  
  

• func findEvenNumbers(digits []int) []int {
  	counter := count(digits)
  	var ans []int
  	for i := 100; i < 1000; i += 2 {
  		t := make([]int, 3)
  		k := i
  		for j := 0; k > 0; j++ {
  			t[j] = k % 10
  			k /= 10
  		}
  		cnt := count(t)
  		if check(counter, cnt) {
  			ans = append(ans, i)
  		}
  	}
  	return ans
  }
  
  func count(nums []int) []int {
  	counter := make([]int, 10)
  	for _, num := range nums {
  		counter[num]++
  	}
  	return counter
  }
  
  func check(cnt1, cnt2 []int) bool {
  	for i := 0; i < 10; i++ {
  		if cnt1[i] < cnt2[i] {
  			return false
  		}
  	}
  	return true
  }
  

• function findEvenNumbers(digits: number[]): number[] {
      let record = new Array(10).fill(0);
      for (let digit of digits) {
          record[digit]++;
      }
      let ans = [];
      for (let i = 100; i < 1000; i += 2) {
          if (check(record, String(i))) {
              ans.push(i);
          }
      }
      return ans;
  }
  
  function check(target: Array<number>, digits: string): boolean {
      let record = new Array(10).fill(0);
      for (let digit of digits) {
          record[digit]++;
      }
  
      for (let i = 0; i < 10; i++) {
          if (record[i] > target[i]) return false;
      }
      return true;
  }
  
  

• /**
   * @param {number[]} digits
   * @return {number[]}
   */
  var findEvenNumbers = function (digits) {
      const cnt = Array(10).fill(0);
      for (const x of digits) {
          ++cnt[x];
      }
      const ans = [];
      for (let x = 100; x < 1000; x += 2) {
          const cnt1 = Array(10).fill(0);
          for (let y = x; y; y = Math.floor(y / 10)) {
              ++cnt1[y % 10];
          }
          let ok = true;
          for (let i = 0; i < 10 && ok; ++i) {
              ok = cnt[i] >= cnt1[i];
          }
          if (ok) {
              ans.push(x);
          }
      }
      return ans;
  };
  
  

All Problems

All Solutions