Created
July 3, 2022 04:35
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LeetCode Weekly Contest 300
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class Solution: | |
def countPaths(self, grid: List[List[int]]) -> int: | |
rows, cols = len(grid), len(grid[0]) | |
dp = {} | |
def dfs(r, c, previous_val): | |
if r < 0 or r == rows or \ | |
c < 0 or c == cols or \ | |
grid[r][c] <= previous_val: | |
return 0 | |
if (r, c) in dp: | |
return dp[(r, c)] | |
res = 1 | |
res += dfs(r + 1, c, grid[r][c]) | |
res += dfs(r - 1, c, grid[r][c]) | |
res += dfs(r, c + 1, grid[r][c]) | |
res += dfs(r, c - 1, grid[r][c]) | |
dp[(r, c)] = res | |
return res | |
for r in range(rows): | |
for c in range(cols): | |
dfs(r, c, -1) | |
return sum(dp.values()) % (10**9 + 7) |
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class Solution: | |
def peopleAwareOfSecret(self, n: int, delay: int, forget: int) -> int: | |
states = {1: 1} # date_start: num_people_known | |
current_date = delay | |
while current_date <= n: | |
new_person_known = 0 | |
person_forgets = {} | |
for date_start, num_people_known in states.items(): | |
if current_date - date_start >= delay: | |
if current_date - date_start < forget: | |
new_person_known += num_people_known | |
else: | |
person_forgets[date_start] = num_people_known | |
# Remove person | |
for date in person_forgets.keys(): | |
states[date] -= person_forgets[date] | |
if states[date] <= 0: | |
del states[date] | |
# Add new person | |
if new_person_known != 0: | |
states[current_date] = new_person_known | |
# print(f"After day {current_date}, {new_person_known} new people know the secret, {sum(person_forgets.values())} people forget the secret, {states}, ans is {sum(states.values())}") | |
current_date += 1 | |
return sum(states.values()) % (10**9 + 7) |
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