Create Basic Algorithms using Python.py

Author: thakurkunal908

Basic Algorithms using Python.py

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+# Binary Search
+
+def binarySearch(num,arr):
+    beg = 0
+    end = len(arr)-1
+    while(beg<=end):
+        mid = (beg+end)//2
+        if(arr[mid]==num):
+            return mid 
+        elif(arr[mid]>num):
+            end = mid - 1
+        else:
+            beg = mid + 1
+    return -1
+    
+#Binary Search Using Recursion
+
+def binarySearch(num,arr,beg,end):
+    if(beg>end):
+        print("NOT FOUND")
+        return
+    mid = (beg + end)//2
+    if(arr[mid]==num):
+        print("FOUND AT ",mid)
+    elif(arr[mid]>num):
+        binarySearch(num,arr,beg,mid-1)
+    else:
+        binarySearch(num,arr,mid+1,end)
+
+
+# Bubble Sort
+
+def bubbleSort(arr):
+    for i in range(0,len(arr)-1):
+        for j in range(0,len(arr)-i-1):
+            if(arr[j+1]<arr[j]):
+                (arr[j],arr[j+1])=(arr[j+1],arr[j])
+
+arr=[5,1,4,2,8,9]
+bubbleSort(arr)
+print(arr)
+
+
+#insetion sort
+
+def insertionSort(arr):
+    for i in range(1,len(arr)):
+        pos = i
+        while(pos>0 and arr[pos-1]>arr[pos]):
+            (arr[pos-1],arr[pos])=(arr[pos],arr[pos-1])
+            pos=pos-1
+arr=[5,1,4,2,8,9]
+insertionSort(arr)
+print(arr)
+
+
+# Selection Sort
+
+def selectionSort(arr):
+    for i in range(len(arr)):
+        minpos = i
+        for j in range(i,len(arr)):
+            if(arr[j]<arr[minpos]):
+                minpos=j
+        (arr[i],arr[minpos])=(arr[minpos],arr[i])
+
+arr=[5,1,4,2,8,9]
+selectionSort(arr)
+print(arr)
+
+
+#Quick Sort Choosing Pivot as the Last Element
+
+def partition(arr,low,high):
+    i = low - 1
+    pivot = arr[high]
+    for j in range(low,high):
+        if(arr[j]<=pivot):
+            i=i+1
+            (arr[i],arr[j])=(arr[j],arr[i])
+    (arr[i+1],arr[high])=(arr[high],arr[i+1])
+    return i+1
+def quickSort(arr,low,high):
+    if(low<high):
+        part = partition(arr,low,high)
+        quickSort(arr,low,part-1)
+        quickSort(arr,part+1,high)
+arr=[2,1,3,4,4,0,9]
+quickSort(arr,0,len(arr)-1)
+print(arr)
+
+
+
+# QuickSort 
+
+def quickSort(arr,low,high):
+    if(low<high):
+        i=low
+        j=low+1
+        while(j<=high):
+            if(arr[j]<=arr[low]):
+                i=i+1
+                (arr[j],arr[i])=(arr[i],arr[j])
+            j=j+1
+        (arr[i],arr[low])=(arr[low],arr[i])
+        part = i
+        quickSort(arr,low,part-1)
+        quickSort(arr,part+1,high)
+arr=[2,1,3,4,4,0,9,-2,-1]
+quickSort(arr,0,len(arr)-1)
+print(arr)
+
+
+#Quick Sort Choosing Pivot as the Last Element
+
+def partition(arr,low,high):
+    i=low
+    j=low+1
+    while(j<=high):
+        if(arr[j]<=arr[low]):
+            i=i+1
+            (arr[j],arr[i])=(arr[i],arr[j])
+        j=j+1
+    (arr[i],arr[low])=(arr[low],arr[i])
+    return i   
+def quickSort(arr,low,high):
+    if(low<high):
+        part = partition(arr,low,high)
+        quickSort(arr,low,part-1)
+        quickSort(arr,part+1,high)
+arr=[2,1,3,4,4,0,9]
+quickSort(arr,0,len(arr)-1)
+print(arr)
+
+
+#Merge Sort
+
+def merge(arr,beg,mid,end):
+    i=beg
+    j=mid+1
+    temp = []
+    while(i<=mid and j<=end):
+        if(arr[i]>=arr[j]):
+            temp.append(arr[j])
+            j=j+1
+        if(arr[j]>arr[i]):
+            temp.append(arr[i])
+            i=i+1
+    if(i>mid):
+        while(j<=end):
+            temp.append(arr[j])
+            j=j+1
+    if(j>end):
+        while(i<=mid):
+            temp.append(arr[i])
+            i=i+1
+    k=0
+    for i in range(beg,end+1):
+        arr[i] = temp[k]
+        k=k+1
+def mergesort(arr,beg,end): 
+    if(beg<end):
+        mid = (beg+end)//2
+        mergesort(arr,beg,mid)
+        mergesort(arr,mid+1,end)
+        merge(arr,beg,mid,end)
+        
+arr=[2,1,3,4,4,0,9]
+mergesort(arr,0,len(arr)-1)
+print(arr)
+
+
+# BFS
+
+def bfs(arr,start):
+    visited = []
+    parent=[]
+    q=[]
+    for i in range(len(arr)):
+        visited.append(start)
+        visited[start]=1 
+        parent.append(-1)
+    q.append(start)
+    while(len(q)!=0):
+        j = q.pop(0)
+        print(j," -->")
+        for k in range(len(arr[j])):
+            if(visited[arr[j][k]]==0):
+                visited[arr[j][k]]=1
+                parent[arr[j][k]]=j
+                q.append(arr[j][k])
+
+
+# DFS
+
+n=int(input("Enter Number of Nodes :"))
+arr=[]
+for i in range(n):
+    l=[int(x) for x in input().split()]
+    arr.append(l)
+visited = [0]*n
+parent = [-1]*n
+def dfs(start):
+    visited[start] = 1
+    print(start)
+    for i in range(len(arr[start])):
+        if(visited[arr[start][i]]==0):
+            parent[arr[start][i]] = start
+            dfs(arr[start][i])
+dfs(0)
+