CODEWITHSUNDEEP
pythonpython-3.x
Pallab Tewary
Pallab Tewary

Reputation: 123

I was Trying Merge sort but Not getting proper output

I was Trying Merge sort but Not getting proper output

getting output [0,0,0,0,0,0,0]

value is not merging in my array b why ? what's wrong in the code?

can anyone please help to Understand this?

def merge(a, low, high, mid):
        b = [0]*len(a)
        
    
        i = low
        j = mid+1
    
        k = low
        while (i <= mid and j <= high):
            if a[i] < a[j]:
                b[k] = a[i]
    
                i += 1
                k += 1
            else:
                b[k] = a[j]
                j += 1
                k += 1
        while(i <= mid):
            b[k] = a[i]
            i += 1
            k += 1
        while(j <= high):
            b[k] = a[j]
            j += 1
            k += 1
        for i in range(0, len(a)):
            a[i] = b[i]
    
    
    
    
    def mergeSort(a, low, high):
    
        if (low < high):
            mid = (low+high)//2
            mergeSort(a, low, mid)
            mergeSort(a, mid+1, high)
            merge(a, low, high, mid)
    
    
    arr = [55, 3, 100, 32, 5, 1, 22]
    low = 0
    high = len(arr)-1
    mergeSort(arr, low, high)
    print(arr)

Upvotes: 0

Views: 33

Answers (1)

gimix
gimix

Reputation: 3833

Your merge copies in a all the values from b, but only a part of b has been populated, so the next iteration will find a few zeros in a and soon a will only contain zeros. Just replace

        for i in range(0, len(a)):
            a[i] = b[i]

with

        for i in range(low, high+1):
            a[i] = b[i]

Upvotes: 2

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