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English Version

题目描述

给你两个整数数组 arr1 , arr2 和一个整数 d ,请你返回两个数组之间的 距离值 。

距离值 定义为符合此距离要求的元素数目:对于元素 arr1[i] ,不存在任何元素 arr2[j] 满足 |arr1[i]-arr2[j]| <= d

 

示例 1:

输入:arr1 = [4,5,8], arr2 = [10,9,1,8], d = 2
输出:2
解释:
对于 arr1[0]=4 我们有:
|4-10|=6 > d=2 
|4-9|=5 > d=2 
|4-1|=3 > d=2 
|4-8|=4 > d=2 
所以 arr1[0]=4 符合距离要求

对于 arr1[1]=5 我们有:
|5-10|=5 > d=2 
|5-9|=4 > d=2 
|5-1|=4 > d=2 
|5-8|=3 > d=2
所以 arr1[1]=5 也符合距离要求

对于 arr1[2]=8 我们有:
|8-10|=2 <= d=2
|8-9|=1 <= d=2
|8-1|=7 > d=2
|8-8|=0 <= d=2
存在距离小于等于 2 的情况,不符合距离要求 

故而只有 arr1[0]=4 和 arr1[1]=5 两个符合距离要求,距离值为 2

示例 2:

输入:arr1 = [1,4,2,3], arr2 = [-4,-3,6,10,20,30], d = 3
输出:2

示例 3:

输入:arr1 = [2,1,100,3], arr2 = [-5,-2,10,-3,7], d = 6
输出:1

 

提示:

  • 1 <= arr1.length, arr2.length <= 500
  • -10^3 <= arr1[i], arr2[j] <= 10^3
  • 0 <= d <= 100

解法

方法一:暴力枚举

由于 arr1arr2 的长度不超过 500,因此可以直接暴力遍历。

时间复杂度 $O(mn)$,其中 $m$arr1 的长度,$n$ 为 arr2 的长度。

方法二:二分查找

对于 arr1 中的每个元素 a,若在 arr2 中存在 b,使得 b ∈ [a - d, a + d],那么就符合距离要求,不进行累加。

因此,可以先对 arr2 进行排序。然后对于每个元素 a,二分枚举 arr2 判断是否存在符合距离要求的 b

时间复杂度 $O((m + n)logn)$

Python3

class Solution:
    def findTheDistanceValue(self, arr1: List[int], arr2: List[int], d: int) -> int:
        return sum(all(abs(a - b) > d for b in arr2) for a in arr1)
class Solution:
    def findTheDistanceValue(self, arr1: List[int], arr2: List[int], d: int) -> int:
        def check(a):
            idx = bisect_left(arr2, a - d)
            if idx != len(arr2) and arr2[idx] <= a + d:
                return False
            return True

        arr2.sort()
        return sum(check(a) for a in arr1)

Java

class Solution {
    public int findTheDistanceValue(int[] arr1, int[] arr2, int d) {
        int ans = 0;
        for (int a : arr1) {
            if (check(arr2, a, d)) {
                ++ans;
            }
        }
        return ans;
    }

    private boolean check(int[] arr, int a, int d) {
        for (int b : arr) {
            if (Math.abs(a - b) <= d) {
                return false;
            }
        }
        return true;
    }
}
class Solution {
    public int findTheDistanceValue(int[] arr1, int[] arr2, int d) {
        Arrays.sort(arr2);
        int ans = 0;
        for (int a : arr1) {
            if (check(arr2, a, d)) {
                ++ans;
            }
        }
        return ans;
    }

    private boolean check(int[] arr, int a, int d) {
        int left = 0, right = arr.length;
        while (left < right) {
            int mid = (left + right) >> 1;
            if (arr[mid] >= a - d) {
                right = mid;
            } else {
                left = mid + 1;
            }
        }
        if (left != arr.length && arr[left] <= a + d) {
            return false;
        }
        return true;
    }
}

C++

class Solution {
public:
    int findTheDistanceValue(vector<int>& arr1, vector<int>& arr2, int d) {
        int ans = 0;
        for (int& a : arr1)
            ans += check(arr2, a, d);
        return ans;
    }

    bool check(vector<int>& arr, int a, int d) {
        for (int& b : arr)
            if (abs(a - b) <= d)
                return false;
        return true;
    }
};
class Solution {
public:
    int findTheDistanceValue(vector<int>& arr1, vector<int>& arr2, int d) {
        sort(arr2.begin(), arr2.end());
        int ans = 0;
        for (int& a : arr1)
            if (check(arr2, a, d))
                ++ans;
        return ans;
    }

    bool check(vector<int>& arr, int a, int d) {
        int idx = lower_bound(arr.begin(), arr.end(), a - d) - arr.begin();
        if (idx != arr.size() && arr[idx] <= a + d) return false;
        return true;
    }
};

Go

func findTheDistanceValue(arr1 []int, arr2 []int, d int) int {
	check := func(arr []int, a int) bool {
		for _, b := range arr {
			if -d <= a-b && a-b <= d {
				return false
			}
		}
		return true
	}

	ans := 0
	for _, a := range arr1 {
		if check(arr2, a) {
			ans++
		}
	}
	return ans
}
func findTheDistanceValue(arr1 []int, arr2 []int, d int) int {
	sort.Ints(arr2)
	check := func(a int) bool {
		left, right := 0, len(arr2)
		for left < right {
			mid := (left + right) >> 1
			if arr2[mid] >= a-d {
				right = mid
			} else {
				left = mid + 1
			}
		}
		if left != len(arr2) && arr2[left] <= a+d {
			return false
		}
		return true
	}
	ans := 0
	for _, a := range arr1 {
		if check(a) {
			ans++
		}
	}
	return ans
}

TypeScript

function findTheDistanceValue(
    arr1: number[],
    arr2: number[],
    d: number,
): number {
    let res = 0;
    for (const num of arr1) {
        if (arr2.every(v => Math.abs(num - v) > d)) {
            res++;
        }
    }
    return res;
}
function findTheDistanceValue(
    arr1: number[],
    arr2: number[],
    d: number,
): number {
    arr2.sort((a, b) => a - b);
    const n = arr2.length;
    let res = 0;
    for (const num of arr1) {
        let left = 0;
        let right = n - 1;
        while (left < right) {
            const mid = (left + right) >>> 1;
            if (arr2[mid] <= num) {
                left = mid + 1;
            } else {
                right = mid;
            }
        }
        if (
            Math.abs(num - arr2[left]) <= d ||
            (left !== 0 && Math.abs(num - arr2[left - 1]) <= d)
        ) {
            continue;
        }
        res++;
    }
    return res;
}

Rust

impl Solution {
    pub fn find_the_distance_value(arr1: Vec<i32>, arr2: Vec<i32>, d: i32) -> i32 {
        let mut res = 0;
        for num in arr1.iter() {
            if arr2.iter().all(|v| i32::abs(num - v) > d) {
                res += 1;
            }
        }
        res
    }
}
impl Solution {
    pub fn find_the_distance_value(arr1: Vec<i32>, mut arr2: Vec<i32>, d: i32) -> i32 {
        arr2.sort();
        let n = arr2.len();
        let mut res = 0;
        for &num in arr1.iter() {
            let mut left = 0;
            let mut right = n - 1;
            while left < right {
                let mid = left + (right - left) / 2;
                if arr2[mid] <= num {
                    left = mid + 1;
                } else {
                    right = mid;
                }
            }
            if i32::abs(num - arr2[left]) <= d || (left != 0 && i32::abs(num - arr2[left - 1]) <= d) {
                continue;
            }
            res += 1;
        }
        res
    }
}

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