Can any one explain the approach to solve this problem
problem - D. Flowers
make linear dp
dp[i] = dp[i-1] + dp[i-k]; (red flower at this index + group of k white flowers finish at that index)
then make commulative sum array for this
sum[i] = dp[i] + sum[i-1]
Now you can solve query in O(1)
sum[b]-sum[a-1]