Leetcode Contest 410 Solutions

Wed, 14 Aug 2024 00:00:00 +0000

class Solution:
 def finalPositionOfSnake(self, n: int, commands: List[str]) -> int:
 grid = [[0 for _ in range(n)] for _ in range(n)]
 idx = 0
 for i in range(n):
 for j in range(n):
 grid[i][j] = idx;
 idx += 1;
 r = 0
 c = 0
 for i in range(len(commands)):
 cm = commands[i]
 if cm == "UP":
 r -= 1
 elif cm == "RIGHT":
 c += 1
 elif cm == "DOWN":
 r += 1
 else:
 c -= 1

 return grid[r][c]

class Solution:
 def countGoodNodes(self, edges: List[List[int]]) -> int:

 n = len(edges) + 1
 graph = [[] for _ in range(n)]

 for [a, b] in edges:
 graph[a].append(b)
 graph[b].append(a)


 ret = 0

 def dfs(node, parent):
 nonlocal ret
 cnts = []
 valids= []
 for nxt in graph[node]:
 if nxt == parent:
 continue
 valid, cnt = dfs(nxt, node)
 valids.append(valid)
 cnts.append(cnt)

 if len(set(cnts)) <= 1:
 ret += 1
 return True, 1 + sum(cnts)
 else:
 return False, 1 + sum(cnts)



 dfs(0, -1)
 return ret

class Solution:
 def countOfPairs(self, nums: List[int]) -> int:
 MOD = int(1e9 + 7)
 n = len(nums)
 m = max(nums) + 1

 dp = [[0 for _ in range(m + 1)] for _ in range(n + 1)]
 for i in range(n):
 for j in range(m + 1):
 if i == 0:
 if nums[i] - j >= 0:
 dp[i][j] = 1
 else:
 dp[i][j] = 0
 else:
 for k in range(j + 1):
 if nums[i - 1] - k >= nums[i] - j and nums[i] - j >= 0:
 dp[i][j] = (dp[i][j] + dp[i - 1][k]) % MOD

 return sum(dp[n - 1]) % MOD

class Solution:
 def countOfPairs(self, nums: List[int]) -> int:
 MOD = int(1e9 + 7)
 n = len(nums)
 m = max(nums) + 1

 dp = [[0 for _ in range(m + 1)] for _ in range(n + 1)]
 p1 = [0 for _ in range(m + 2)]
 p2 = [0 for _ in range(m + 2)]
 for i in range(n):
 for j in range(m + 1):
 if i == 0:
 if nums[i] - j >= 0:
 dp[i][j] = 1
 else:
 dp[i][j] = 0
 else:
 k = nums[i - 1] - nums[i] + j
 if nums[i] - j >= 0:
 if k >= m:
 k = m
 if k < 0:
 dp[i][j] = 0
 continue
 if k >= j:
 k = j
 dp[i][j] = p1[k]
 else:
 dp[i][j] = 0

 if j != 0:
 p2[j] = (p2[j - 1] + dp[i][j]) % MOD
 else:
 p2[j] = (0 + dp[i][j]) % MOD

 p1 = list(p2)
 p2 = [0 for _ in range(m + 2)]



 return sum(dp[n - 1]) % MOD

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Leetcode Contest 410 Solutions