Skip to content

658. Find K Closest Elements

Description

Given a sorted integer array arr, two integers k and x, return the k closest integers to x in the array. The result should also be sorted in ascending order.

An integer a is closer to x than an integer b if:

  • |a - x| < |b - x|, or
  • |a - x| == |b - x| and a < b

 

Example 1:

Input: arr = [1,2,3,4,5], k = 4, x = 3

Output: [1,2,3,4]

Example 2:

Input: arr = [1,1,2,3,4,5], k = 4, x = -1

Output: [1,1,2,3]

 

Constraints:

  • 1 <= k <= arr.length
  • 1 <= arr.length <= 104
  • arr is sorted in ascending order.
  • -104 <= arr[i], x <= 104

Solutions

Solution 1: Sort

1
2
3
4
class Solution:
    def findClosestElements(self, arr: List[int], k: int, x: int) -> List[int]:
        arr.sort(key=lambda v: abs(v - x))
        return sorted(arr[:k])

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
class Solution {
    public List<Integer> findClosestElements(int[] arr, int k, int x) {
        List<Integer> ans = Arrays.stream(arr)
                                .boxed()
                                .sorted((a, b) -> {
                                    int v = Math.abs(a - x) - Math.abs(b - x);
                                    return v == 0 ? a - b : v;
                                })
                                .collect(Collectors.toList());
        ans = ans.subList(0, k);
        Collections.sort(ans);
        return ans;
    }
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
int target;

class Solution {
public:
    static bool cmp(int& a, int& b) {
        int v = abs(a - target) - abs(b - target);
        return v == 0 ? a < b : v < 0;
    }

    vector<int> findClosestElements(vector<int>& arr, int k, int x) {
        target = x;
        sort(arr.begin(), arr.end(), cmp);
        vector<int> ans(arr.begin(), arr.begin() + k);
        sort(ans.begin(), ans.end());
        return ans;
    }
};

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
func findClosestElements(arr []int, k int, x int) []int {
    sort.Slice(arr, func(i, j int) bool {
        v := abs(arr[i]-x) - abs(arr[j]-x)
        if v == 0 {
            return arr[i] < arr[j]
        }
        return v < 0
    })
    ans := arr[:k]
    sort.Ints(ans)
    return ans
}

func abs(x int) int {
    if x >= 0 {
        return x
    }
    return -x
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
function findClosestElements(arr: number[], k: number, x: number): number[] {
    let l = 0;
    let r = arr.length;
    while (r - l > k) {
        if (x - arr[l] <= arr[r - 1] - x) {
            --r;
        } else {
            ++l;
        }
    }
    return arr.slice(l, r);
}