二分搜索

Author: tianqing.liang

README.md

@@ -11,7 +11,7 @@
 6. 递归
 7. **[Dart,Python]归并排序**
 8. **[Dart,Python]快速排序**
-9. 二分搜索
+9. **[Dart,Python]二分搜索**
 10. 二分搜索树
 11. 集合 和 映射
 12. 堆

python/linkedlist.py

@@ -7,7 +7,25 @@ def __init__(self,value=None,next=None):
     def __str__(self):
         return self.value;
 
+class LinkedList(object):
+
+    def __init__(self):
+        self.__head = None
+        self.__size = 0
+        
+    def getSize(self):
+        return self.__size
+    
+    def isEmpty(self):
+        return self.__size == 0;
 
+    def remove(self,index):
+        if index<0 or index> self.__size:
+            raise Exception("Remove Failed,Illegal index")
+        prev = self.__head
+        for i in range(0,index):
+            prev = prev.next
+        
 
 
 
@@ -27,27 +45,10 @@ def __str__(self):
 
 
 
-# class LinkedList<T> {
-#   _Node? _dummyHead;
-#   late int _size;
-
-#   LinkedList() {
-#     _dummyHead = new _Node.withEmpty();
-#     _size = 0;
-#   }
-
-#   int getSize() {
-#     return _size;
-#   }
-
-#   bool isEmpty() {
-#     return _size == 0;
-#   }
 
+# class LinkedList<T> {
 #   remove(int index){
-#     if (index < 0 || index > _size) {
-#       throw Exception("Remove Failed,Illegal index");
-#     }
+#     
 #     _Node? prev = _dummyHead;
 #     for(var i =0;i<index ;i++){
 #       prev = prev?.next;

python/multiSort.py

@@ -4,6 +4,8 @@
     选择排序
     插入排序
     希尔排序
+    快速排序
+    归并排序
 '''
 import random
 import time
@@ -85,24 +87,38 @@ def partition(sortList,left,right):
     return i +1    
 
 # 归并排序
-def merge(arr1, arr2): 
+def merge(sortList1, sortList2): 
     result = []
     while arr1 and arr2:
-        if arr1[0] < arr2[0]:
-            result.append(arr1.pop(0))
+        if sortList1[0] < sortList2[0]:
+            result.append(sortList1.pop(0))
         else:
-            result.append(arr2.pop(0))
-    if arr1:
-        result += arr1
-    if arr2:
-        result += arr2
+            result.append(sortList2.pop(0))
+    if sortList1:
+        result += sortList1
+    if sortList2:
+        result += sortList2
     return result
 
-def merge_sort(arr):
-    if len(arr) <= 1:
+def merge_sort(sortList):
+    if len(sortList) <= 1:
         return arr
-    mid = len(arr) // 2
-    return merge(merge_sort(arr[:mid]), merge_sort(arr[mid:]))
+    mid = len(sortList) // 2
+    return merge(merge_sort(sortList[:mid]), merge_sort(sortList[mid:]))
+
+# 二分搜索
+def binarySearch(sortList,left,right,x):
+    if right >= left :
+        mid = int(left + (right-left)/2)
+        if sortList[mid] == x:
+            return mid
+        elif sortList[mid] >x:
+            return binarySearch(sortList, left, mid-1, x) 
+        else:
+            return binarySearch(sortList, mid+1, right, x)
+    else:
+        return -1 
+
 
 # 计算结果，计算时间
 def caculateResultAndTime(name,fuction,randomseed):
@@ -133,6 +149,15 @@ def caculateResultAndTime(name,fuction,randomseed):
     print("排序结果:",sortList,' 花费时间：',endTime-startTime)
     print("-------------------- 结束\n")
 
+    print("--------------------二分搜索")
+    sortList = list(range(15))
+    print("原始数据：",sortList)
+    startTime = time.perf_counter()
+    result = binarySearch(sortList, 0, len(sortList)-1,10)
+    endTime = time.perf_counter()
+    print("查找结果:",result,' 花费时间：',endTime-startTime)
+    print("-------------------- 结束\n")
+