按右侧边界升序排列

CodingProgrammer · web-flow · commit ba5003f17ac4 · 2020-11-24T16:09:40.000+08:00
diff --git a/贪心算法/452用最少数量的箭引爆气球.py b/贪心算法/452用最少数量的箭引爆气球.py
@@ -0,0 +1,70 @@
+'''
+Descripttion: 用最少数量的箭引爆气球
+version: 1
+Author: Jason
+Date: 2020-11-24 14:40:10
+LastEditors: Jason
+LastEditTime: 2020-11-24 16:00:31
+'''
+
+import random
+from typing import List
+
+
+def GenerateRandomList(left_bound, right_bound, numbers):
+    temp = list()
+    random_legth = random.randint(0, numbers)
+    current_length = 0
+    while current_length < random_legth:
+        left_point = random.randint(0, left_bound)
+        right_point = random.randint(left_point + 1, right_bound)
+        temp.append([left_point, right_point])
+        current_length += 1
+    return temp
+
+
+class Solution:
+    def findMinArrowShots(self, points: List[List[int]]) -> int:
+        points.sort(key=lambda point: point[1])
+        arrows = 0
+        boundary = float("-inf")
+        for point in points:
+            if point[0] > boundary:
+                arrows += 1
+                boundary = point[1]
+        return arrows
+
+    def findMinArrowShots2(self, points: List[List[int]]) -> int:
+        '''
+        func: 按开始位置排序，维护gap区域，如果当前点不在gap范围内，则arrows+1，且将gap更新为当前点的区间
+        param {*}
+        return {*}
+        '''
+        if len(points) < 1:
+            return 0
+        points.sort()
+        arrows = 1
+        gap = [float("-inf"), float("inf")]
+        for each in points:
+            if gap[0] <= each[0] <= gap[1] or gap[0] <= each[1] <= gap[1]:
+                gap = [max(gap[0], each[0]), min(gap[1], each[1])]
+                continue
+            gap = each
+            arrows += 1
+        return arrows
+
+
+s = Solution()
+for i in range(100):
+    points = GenerateRandomList(30, 60, 20)
+# print("**********************************************")
+# print(points)
+    points2 = points[::]
+    res = s.findMinArrowShots(points[::])
+    res2 = s.findMinArrowShots2(points2)
+    # print("res: %d     res2: %d" % (res, res2))
+    if res != res2:
+        print("***************************************")
+        print(points)
+        print("Wrong")
+print("Done!")
