bisect search

Author: Ehco1996

ehco/search/search.py

@@ -0,0 +1,121 @@
+number_list = [0, 1, 2, 3, 4, 5, 6, 7]
+
+
+def linear_search(value, array):
+    for index, val in enumerate(array):
+        if val == value:
+            return index
+    return -1
+
+
+assert linear_search(5, number_list) == 5
+
+
+def linear_search_recusive(value, array):
+    if len(array) == 0:
+        return -1
+    index = len(array) - 1
+    if array[index] == value:
+        return index
+    else:
+        return linear_search_recusive(value, array[0:index])
+
+
+assert linear_search_recusive(5, number_list) == 5
+assert linear_search_recusive(8, number_list) == -1
+assert linear_search_recusive(7, number_list) == 7
+assert linear_search_recusive(0, number_list) == 0
+
+
+def binary_search(value, array):
+    if not array:
+        return -1
+
+    beg = 0
+    end = len(array) - 1
+
+    while beg <= end:
+        mid = int((beg + end) / 2)
+        if array[mid] == value:
+            return mid
+        elif array[mid] > value:
+            end = mid - 1
+        else:
+            beg = mid + 1
+    return -1
+
+
+def test_binary_search():
+    a = list(range(10))
+
+    # 正常值
+    assert binary_search(-1, a) == -1
+    assert binary_search(1, a) == 1
+
+    # 异常值
+    assert binary_search(1, None) == -1
+
+    # 边界值
+    assert binary_search(0, a) == 0
+
+
+test_binary_search()
+
+
+def binary_search_recusive(value, array):
+    if not array:
+        return -1
+
+    beg = 0
+    end = len(array) - 1
+    mid = int((beg + end) / 2)
+    if mid == value:
+        return mid
+    elif array[mid] > value:
+        return binary_search_recusive(value, array[0:mid])
+    else:
+        return binary_search_recusive(value, array[mid:end])
+
+
+def test_binary_search_recusive():
+    a = list(range(10))
+
+    # 正常值
+    assert binary_search_recusive(-1, a) == -1
+    assert binary_search_recusive(1, a) == 1
+
+    # 异常值
+    assert binary_search_recusive(1, None) == -1
+
+    # 边界值
+    assert binary_search_recusive(0, a) == 0
+
+
+test_binary_search_recusive()
+
+
+def bisect_own(value, array):
+    if not array:
+        return -1
+
+    lo = 0
+    end = len(array)
+
+    while lo < end:
+        mid = int((lo + end) / 2)
+        if array[mid] < value:
+            lo = mid + 1
+        else:
+            end = mid
+    return lo
+
+
+def test_bisect_own():
+    a = list(range(10))
+
+    # 正常值
+    assert bisect_own(-1, a) == 0
+    assert bisect_own(11, a) == 10
+
+
+test_bisect_own()