2020-08-22

Author: JiayangWu

1535.找出数组游戏的赢家/1535-找出数组游戏的赢家.py

@@ -5,15 +5,15 @@ def getWinner(self, arr, k):
         :type k: int
         :rtype: int
         """
-        pre = max(arr[0], arr[1])
+        winner = max(arr[0], arr[1])
         cnt = 1
         for num in arr[2:]:
             if cnt == k:
-                return pre
-            if pre > num:
+                return winner
+            if winner > num:
                 cnt += 1
             else:
-                pre = num 
+                #刷新winner
+                winner = num 
                 cnt = 1
-        return pre
-            
+        return winner

1536.排布二进制网格的最少交换次数/1536-排布二进制网格的最少交换次数.py

@@ -4,10 +4,9 @@ def minSwaps(self, grid):
         :type grid: List[List[int]]
         :rtype: int
         """
-        from collections import defaultdict, deque
-        dic = dict()
+        dic = dict() # key 是每行的idx， val 是这一行末尾0的个数
         n = len(grid)
-        for i, row in enumerate(grid):
+        for i, row in enumerate(grid): # 统计每一行末尾有几个0
             cnt = 0
             for j in range(n - 1, -1, -1):
                 if not row[j]:
@@ -18,17 +17,15 @@ def minSwaps(self, grid):
 
         res = 0
         for i in range(n):
-            zero_cnt = dic[i]
-
-            if zero_cnt < n - i - 1:
+            if dic[i] < n - i - 1: # 这一行0太少，需要放到下面去
                 for j in range(i + 1, n):
-                    if dic[j] >= n - i - 1:
+                    if dic[j] >= n - i - 1: # 找到0足够多的行
                         break 
-                if dic[j] < n - i - 1:
+                if dic[j] < n - i - 1: # 没找到说明无解
                     return -1
-                tmp = dic[j]
-                res += j - i
-                for k in range(j, i, -1):
+
+                for k in range(j, i, -1): #把第i行换到第j行的位置上去
                     dic[k] = dic[k - 1]
-            
-        return res
+
+                res += j - i
+        return res