033 - Algorithms on Arrays - Re-arrange elements in an array to put positive and negative elements in alternate order | C# Online Compiler

033 - Algorithms on Arrays - Re-arrange elements in an array to put positive and negative elements in alternate order by billaraw

using System;
					
public class Program
{
	public static void Main()
	{
		int[] arr = new int[]{-1,3,2,4,5,-6,7,-9};
		
		int lastSwapPost = 0;
		for(var i = 0; i < arr.Length; i++){
			
			//Current is Neg but should be pos.
			if(i % 2 == 0 && arr[i] < 0)
			{
				//Console.WriteLine("Current is Neg but should be pos:" + i);
				int? nextPos = null;
				if(i == arr.Length - 1 && lastSwapPost < arr.Length - 1){
					rotateArr(arr, lastSwapPost, i);
				}else{
					for(var j = i + 1; j < arr.Length; j ++)
					{
						if(arr[j] > 0)
						{
							nextPos = j;
							break;
						}
					}
					//Console.WriteLine("nextPos:" + nextPos);
					if(nextPos != null){
						rotateArr(arr, i, (int)nextPos);
						lastSwapPost = i + 2;
					}
					//Console.WriteLine("lastSwapPost:" + lastSwapPost);
					//Console.WriteLine(String.Join(",", arr));
				}
			}
			else if(i % 2 == 1 && arr[i] > 0){
				//Current is Pos but should be neg.
				//Console.WriteLine("Current is Pos but should be neg:" + i);
				if(i == arr.Length - 1 && lastSwapPost < arr.Length - 1){
					rotateArr(arr, lastSwapPost, i);
				}else{
					int? nextPos = null;
					for(var j = i + 1; j < arr.Length; j ++)
					{
						if(arr[j] < 0)
						{
							nextPos = j;
							break;
						}
					}
					//Console.WriteLine("nextPos:" + nextPos);
					if(nextPos != null){
						rotateArr(arr, i, (int)nextPos);
						lastSwapPost = i + 2;
					}
					//Console.WriteLine("lastSwapPost:" + lastSwapPost);
					//Console.WriteLine(String.Join(",", arr));
				}
			}
		}
		
		Console.WriteLine(String.Join(",", arr));
	}
			
	public static void rotateArr(int[] arr, int start, int end){
		
		Console.WriteLine("start:" + String.Join(",", arr));
		Console.WriteLine("start:" + start + " end:" + end);
		var tmp = arr[start];
		var tmp2 = 0;
		
		for(var i = start; i <= end; i++){
			if(i == end){
				arr[start] = tmp;
				break;
			}else{
				tmp2 = arr[i+1];
				arr[i+1] = tmp;
				tmp = tmp2;
			}
		}
		Console.WriteLine("start:" + String.Join(",", arr));
	}
}

 
using System;
                    
public class Program
{
    public static void Main()
    {
        int[] arr = new int[]{-1,3,2,4,5,-6,7,-9};
        
        int lastSwapPost = 0;
        for(var i = 0; i < arr.Length; i++){
            
            //Current is Neg but should be pos.
            if(i % 2 == 0 && arr[i] < 0)
            {
                //Console.WriteLine("Current is Neg but should be pos:" + i);
                int? nextPos = null;
                if(i == arr.Length - 1 && lastSwapPost < arr.Length - 1){
                    rotateArr(arr, lastSwapPost, i);
                }else{
                    for(var j = i + 1; j < arr.Length; j ++)
                    {
                        if(arr[j] > 0)
                        {
                            nextPos = j;
                            break;
                        }
                    }
                    //Console.WriteLine("nextPos:" + nextPos);
                    if(nextPos != null){
                        rotateArr(arr, i, (int)nextPos);
                        lastSwapPost = i + 2;
                    }
                    //Console.WriteLine("lastSwapPost:" + lastSwapPost);
                    //Console.WriteLine(String.Join(",", arr));
                }
            }
            else if(i % 2 == 1 && arr[i] > 0){
                //Current is Pos but should be neg.
                //Console.WriteLine("Current is Pos but should be neg:" + i);
                if(i == arr.Length - 1 && lastSwapPost < arr.Length - 1){
                    rotateArr(arr, lastSwapPost, i);
                }else{
                    int? nextPos = null;
                    for(var j = i + 1; j < arr.Length; j ++)
                    {
                        if(arr[j] < 0)
                        {
                            nextPos = j;
                            break;
                        }
                    }
                    //Console.WriteLine("nextPos:" + nextPos);
                    if(nextPos != null){
                        rotateArr(arr, i, (int)nextPos);
                        lastSwapPost = i + 2;
                    }
                    //Console.WriteLine("lastSwapPost:" + lastSwapPost);
                    //Console.WriteLine(String.Join(",", arr));
                }
            }
        }
        
        Console.WriteLine(String.Join(",", arr));
    }
            
    public static void rotateArr(int[] arr, int start, int end){
        
        Console.WriteLine("start:" + String.Join(",", arr));
        Console.WriteLine("start:" + start + " end:" + end);
        var tmp = arr[start];
        var tmp2 = 0;
        
        for(var i = start; i <= end; i++){
            if(i == end){
                arr[start] = tmp;
                break;
            }else{
                tmp2 = arr[i+1];
                arr[i+1] = tmp;
                tmp = tmp2;
            }
        }
        Console.WriteLine("start:" + String.Join(",", arr));
    }
}

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