2020-02-28

1351.统计有序矩阵中的负数/1351-统计有序矩阵中的负数.py

@@ -0,0 +1,16 @@
+class Solution(object):
+    def countNegatives(self, grid):
+        """
+        :type grid: List[List[int]]
+        :rtype: int
+        """
+        if not grid or not grid[0]:
+            return 0
+        m, n = len(grid), len(grid[0])
+
+        res = 0
+        for i in range(m):
+            for j in range(n):
+                if grid[i][j] < 0:
+                    res += 1
+        return res

1352.最后K个数的乘积/1352-最后K个数的乘积.py

@@ -0,0 +1,23 @@
+class ProductOfNumbers(object):
+
+    def __init__(self):
+        self.prefix = [1]
+
+    def add(self, num):
+        """
+        :type num: int
+        :rtype: None
+        """
+        if num:
+            self.prefix.append(self.prefix[-1] * num)
+        else:
+            self.prefix = [1]
+
+    def getProduct(self, k):
+        """
+        :type k: int
+        :rtype: int
+        """
+        if k >= len(self.prefix):
+            return 0
+        return self.prefix[-1] / self.prefix[-k - 1]

1353.最多可以参加的会议数目/1353-最多可以参加的会议数目.py

@@ -0,0 +1,33 @@
+class Solution(object):
+    def maxEvents(self, events):
+        """
+        :type events: List[List[int]]
+        :rtype: int
+        """
+        from heapq import *
+        if not events:
+            return 0
+        # 排序并反转，反转是为了可以快速pop
+        events = sorted(events, key = lambda x:(x[0], x[1]))[::-1]
+
+        queue = []
+        res = 0
+        for day in range(1, 10 ** 5 + 1):
+            # 把所有结束日期在当前日期之前的event都pop掉
+            while queue and queue[0] < day:
+                heappop(queue)
+
+            # 把所有开始日期大于等于当前日期的event都push进队列
+            while events and events[-1][0] <= day:
+                last = events.pop()
+                heappush(queue, last[1])
+
+            if queue:
+                # 如果当前日期有可以去的event，就去这一个
+                heappop(queue)
+                res += 1
+            if not queue and not events:
+                # 如果所有event都参加完了
+                break
+
+        return res

1354.多次求和构造目标数组/1354-多次求和构造目标数组.py

@@ -0,0 +1,29 @@
+class Solution(object):
+    def isPossible(self, target):
+        """
+        :type target: List[int]
+        :rtype: bool
+        """
+        from heapq import *
+        if len(target) == 1:
+            return target[0] == 1
+
+        s = sum(target)
+        target = [-item for item in target]
+        heapify(target)
+
+        while s > len(target):
+            # 找当前最大的数和第二大的数
+            m = -heappop(target)
+            s_m = -target[0]
+
+            # 更新 m 并更新 s
+            diff = s - m             
+            if not diff:
+                break
+            new_m = m - (max(1, (m - s_m) / diff) * diff)
+            s = s - m + new_m
+
+            heappush(target, -new_m)
+
+        return not any([num != -1 for num in target])