从给定的数组中删除所有负数

给定一个大小为N的数组arr[] ，任务是从该数组中删除所有负元素。

例子：

Input: arr[] = {3, -4}
Output: {3}
Explanation: The only negative element of the array is -4.

Input: arr[] = {1, -3, 2}
Output: {1, 2}

方法 1 ：给定问题可以使用以下步骤解决：

1. 创建一个向量newArr以仅存储正元素。
2. 现在遍历数组arr ，并将正元素压入newArr 。
3. 返回newArr作为答案。

下面是上述方法的实现：

C++

// C++ code for the above approach
#include 
using namespace std;
 
// Function to remove the negative elements
void removeNegative(vector& arr)
{
    vector newArr;
 
    for (auto x : arr) {
        if (x >= 0) {
            newArr.push_back(x);
        }
    }
 
    for (auto x : newArr) {
        cout << x << ' ';
    }
}
 
// Driver Code
int main()
{
    vector arr = { 1, -3, 2 };
    removeNegative(arr);
    return 0;
}

Java

// Java code for the above approach
import java.util.ArrayList;
 
class GFG {
 
  // Function to remove the negative elements
  static void removeNegative(int[] arr) {
    ArrayList newArr = new ArrayList();
 
    for (int x : arr) {
      if (x >= 0) {
        newArr.add(x);
      }
    }
 
    for (int x : newArr) {
      System.out.print(x + " ");
    }
  }
 
  // Driver Code
  public static void main(String args[]) {
    int[] arr = { 1, -3, 2 };
    removeNegative(arr);
  }
}
 
// This code is contributed by saurabh_jaiswal.

Python3

# Python code for the above approach
 
# Function to remove the negative elements
def removeNegative(arr):
    newArr = []
 
    for x in range(0, len(arr)):
        if (arr[x] >= 0):
            newArr.append(arr[x])
 
    for x in range(0, len(newArr)):
        print(newArr[x], end=' ')
 
# Driver Code
arr = [1, -3, 2]
removeNegative(arr)
 
# This code is contributed by Taranpreet

C#

// C# code for the above approach
using System;
using System.Collections;
 
class GFG {
 
  // Function to remove the negative elements
  static void removeNegative(int[] arr) {
    ArrayList newArr = new ArrayList();
 
    foreach (int x in arr) {
      if (x >= 0) {
        newArr.Add(x);
      }
    }
 
    foreach (int x in newArr) {
      Console.Write(x + " ");
    }
  }
 
  // Driver Code
  public static void Main() {
    int[] arr = { 1, -3, 2 };
    removeNegative(arr);
  }
}
 
// This code is contributed by Samim Hossain Mondal.

Javascript

        // JavaScript code for the above approach
 
        // Function to remove the negative elements
        function removeNegative(arr)
        {
            let newArr = [];
 
            for (let x of arr) {
                if (x >= 0) {
                    newArr.push(x);
                }
            }
 
            for (let x of newArr) {
                document.write(x + " ")
            }
        }
 
        // Driver Code
        let arr = [1, -3, 2];
        removeNegative(arr);
 
    // This code is contributed by Potta Lokesh
    

输出

1 2 

时间复杂度： 在）
辅助空间： 在）

方法 2（对于Java）： Java 的 lambda函数removeIf()也可用于删除否定元素。

Java

// Java code for above approach
import java.util.*;
 
public class Solution {
 
    // Function to remove the
    // negative elements from the array
    public static ArrayList
    remNeg(ArrayList arr)
    {
        arr.removeIf(n -> n < 0);
        return arr;
    }
 
    // Driver Code
    public static void main(String[] args)
    {
        ArrayList arr
            = new ArrayList(
                Arrays.asList(1, -3, 2));
 
        arr = remNeg(arr);
        for (int i = 0; i < arr.size(); i++) {
            System.out.print(arr.get(i) + " ");
        }
    }
}

C＃

// C# code for above approach
using System;
using System.Collections.Generic;
 
public class Solution {
 
  static bool isEven(int i)
  {
    return i < 0;
  }
 
  // Function to remove the
  // negative elements from the array
  static List
    remNeg(List arr)
  {
    arr.RemoveAll(isEven);
    return arr;
  }
 
  // Driver Code
  public static void Main(String[] args)
  {
    List arr
      = new List(new int[]{1, -3, 2});
 
    arr = remNeg(arr);
    for (int i = 0; i < arr.Count; i++) {
      Console.Write(arr[i] + " ");
    }
  }
}
 
// This code is contributed by shikhasingrajput

Javascript

// javascript code for above approach
 
    // Function to remove the
    // negative elements from the array
     function remNeg( arr) {
     for (var i = 0; i < arr.length; i++) {
            if(arr[i] < 0){
                arr.splice(i,1);
            }
        }
         
        return arr;
    }
 
    // Driver Code
        var arr = [1, -3, 2];
 
        arr = remNeg(arr);
        for (i = 0; i < arr.length; i++) {
            document.write(arr[i] + " ");
        }
 
// This code is contributed by Rajput-Ji

输出

1 2 

时间复杂度： 在）
辅助空间： O(1)