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Number of People Aware of a Secret
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Day-by-Day DP
Prefix Sum (Optimized)
Input
Standard
Simple
Longer
Custom
n
=
6
,
delay
=
2
,
forget
=
4
1
2
3
4
5
6
day
dp
?
?
?
?
?
?
n = 6 delay = 2 forget = 4
1
2
3
4
5
6
day
dp
?
?
?
?
?
?
n = 6 delay = 2 forget = 4
dp[2] =
0
1
2
3
4
5
6
day
dp
1
0
?
?
?
?
i
dp[2] =
0
dp[3] =
1
sum window
1
2
3
4
5
6
day
dp
1
0
1
?
?
?
i
dp[3] =
1
dp[4] =
1
sum window
1
2
3
4
5
6
day
dp
1
0
1
?
?
?
i
dp[4] += dp[2]
0
=
1
dp[5] =
0
sum window
1
2
3
4
5
6
day
dp
1
0
1
1
?
?
i
dp[5] += dp[2]
0
=
0
dp[6] =
1
sum window
1
2
3
4
5
6
day
dp
1
0
1
1
1
?
i
dp[6] += dp[3]
1
=
1
result =
0
1
2
3
4
5
6
day
dp
1
0
1
1
1
2
count cohorts that still remember: i + forget > 6
result =
1
1
2
3
4
5
6
day
dp
1
0
1
1
1
2
i
i + forget =
4 + 4 = 8
>
6
still remembers
result =
3
1
2
3
4
5
6
day
dp
1
0
1
1
1
2
i
result =
2
+ dp[5]
1
=
3
result =
5
1
2
3
4
5
6
day
dp
1
0
1
1
1
2
return
5
algo
master
.
io
Step:
Start: n = 6 days, share after 2, forget after 4.
0 / 28
Input
Standard
Simple
Longer
Custom
n
=
6
,
delay
=
2
,
forget
=
4
0 / 28
algo
master
.
io
Step:
Start: n = 6 days, share after 2, forget after 4.
