searching algorithm added

software · software · commit e07fb4268b53 · 2021-09-24T21:36:41.000+05:00
diff --git a/Searching/issorted.py b/Searching/issorted.py
@@ -0,0 +1,19 @@
+# determine if a list is sorted
+
+
+items1 = [6, 8, 19, 20, 23, 41, 49, 53, 56, 87]
+items2 = [6, 20, 8, 19, 56, 23, 87, 41, 49, 53]
+
+def is_sorted(itemlist):
+    # using the all function
+    return all(itemlist[i] <= itemlist[i+1] for i in range(len(itemlist)-1))
+
+    # using the brute force method
+    # for i in range(0, len(itemlist)-1):
+    #     if (itemlist[i] > itemlist[i+1]):
+    #         return False
+    # return True
+
+print(is_sorted(items1))
+print(is_sorted(items2))
+
diff --git a/Searching/ordered.py b/Searching/ordered.py
@@ -0,0 +1,33 @@
+# searching for an item in an ordered list
+# this technique uses a binary search
+
+
+items = [6, 8, 19, 20, 23, 41, 49, 53, 56, 87]
+
+def binarysearch(item, itemlist):
+    # get the list size
+    listsize = len(itemlist) - 1
+    # start at the two ends of the list
+    lowerIdx = 0
+    upperIdx = listsize
+
+    while lowerIdx <= upperIdx:
+        # calculate the middle point
+        midPt = (lowerIdx + upperIdx)// 2
+
+        # if item is found, return the index
+        if itemlist[midPt] == item:
+            return midPt
+        # otherwise get the next midpoint
+        if item > itemlist[midPt]:
+            lowerIdx = midPt + 1
+        else:
+            upperIdx = midPt - 1
+
+    if lowerIdx > upperIdx:
+        return None
+
+
+print(binarysearch(23, items))
+print(binarysearch(87, items))
+print(binarysearch(250, items))
diff --git a/Searching/unordered.py b/Searching/unordered.py
@@ -0,0 +1,16 @@
+# searching for an item in an unordered list
+# sometimes called a Linear search
+
+# declare a list of values to operate on
+items = [6, 20, 8, 19, 56, 23, 87, 41, 49, 53]
+
+def find_item(item, itemlist):
+    for i in range(0, len(itemlist)):
+        if item == itemlist[i]:
+            return i
+    
+    return None
+
+
+print(find_item(87, items))
+print(find_item(250, items))
