Score : 400 points
We have a string S of length N consisting of R
, G
, and B
.
Find the number of triples (i,~j,~k)~(1 \leq i < j < k \leq N) that satisfy both of the following conditions:
R
, G
, and B
.Input is given from Standard Input in the following format:
N S
Print the number of triplets in question.
4 RRGB
1
Only the triplet (1,~3,~4) satisfies both conditions. The triplet (2,~3,~4) satisfies the first condition but not the second, so it does not count.
39 RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB
1800