2020-03-27

Author: JiayangWu

1389.按既定顺序创建目标数组/1389-按既定顺序创建目标数组.py

@@ -0,0 +1,11 @@
+class Solution(object):
+    def createTargetArray(self, nums, index):
+        """
+        :type nums: List[int]
+        :type index: List[int]
+        :rtype: List[int]
+        """
+        res = []
+        for i in range(len(nums)):
+            res.insert(index[i], nums[i])
+        return res

1390.四因数/1390-四因数.py

@@ -0,0 +1,19 @@
+class Solution(object):
+    def sumFourDivisors(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        def factor(n):
+            l = []
+            for i in range(1, int(n ** 0.5) + 1):
+                if n % i == 0:
+                    l.append(i)
+                    if n / i != i:
+                        l.append(n / i)
+                if len(l) > 4:
+                    break
+
+            return sum(l) if len(l) == 4 else 0 
+
+        return sum(map(factor, nums))

1391.检查网格中是否存在有效路径/1391-检查网格中是否存在有效路径.py

@@ -0,0 +1,33 @@
+class Solution(object):
+    def hasValidPath(self, grid):
+        """
+        :type grid: List[List[int]]
+        :rtype: bool
+        """
+        m, n = len(grid), len(grid[0])
+        dir = {}
+        dir[1] = [0, 1, 0, 1]
+        dir[2] = [1, 0, 1, 0]
+        dir[3] = [0, 0, 1, 1]
+        dir[4] = [0, 1, 1, 0]
+        dir[5] = [1, 0, 0, 1]
+        dir[6] = [1, 1, 0, 0]
+
+        dx = [-1, 0, 1, 0]
+        dy = [0, 1, 0, -1]
+        queue = [(0, 0)]
+        visited = set(queue)
+        
+        cor = {0:2, 1:3, 3:1, 2:0}
+        while queue:
+            x0, y0 = queue.pop()
+            if [x0, y0] == [m - 1, n - 1]:
+                return True
+            for k in range(4):
+                x = x0 + dx[k]
+                y = y0 + dy[k]
+                if 0 <= x < m and 0 <= y < n and (x, y) not in visited and dir[grid[x0][y0]][k] & dir[grid[x][y]][cor[k]]:
+                    visited.add((x, y))
+                    queue.append((x, y))
+        return False
+

1392.最长快乐前缀/1392-最长快乐前缀.py

@@ -0,0 +1,20 @@
+class Solution(object):
+    def longestPrefix(self, s):
+        """
+        :type s: str
+        :rtype: str
+        """
+        base = 131
+        mod = 10 ** 9 + 7
+        res = ""
+        prefix, suffix = 0, 0
+        multiple = 1
+        for i in range(len(s) - 1):
+            prefix = (prefix * base + ord(s[i])) % mod 
+            suffix = (ord(s[-(i + 1)]) * multiple + suffix) % mod 
+            if prefix == suffix:
+                res = s[:i + 1]
+            
+            multiple = multiple * base % mod
+
+        return res