14 out of 19, 13 out of 24, 14 out of 23, 15 out of 19, 13 out of 23

14 out of 19, 13 out of 24, 14 out of 23, 15 out of 19, 13 out of 23

13 of 24, 13 of 23, 14 of 23, 14 of 19, 15 of 19

Direct array size: 2 / 13,7 / 19,14 / 158

7/19>2/13>14/158

1 / 2 + 1 / 3 + 2 / 3 + 1 / 4 + 2 / 4 + 3 / 4 + 1 / 5 + 2 / 5 + +…
1 / 2 + 1 / 3 + 2 / 3 + 1 / 4 + 2 / 4 + 3 / 4 + 1 / 5 + 2 / 5 + +1 / 50 + 2 / 50 + +50:49
(calculation)

Let's look at the formula 1 / N + 2 / N +... + (n-1) / N = (1 + 2 +... + n-1) / N in the high school sequence, 1 + 2 +... + I = I * (I + 1) / 2. (I won't write the derivation here, if you want to know, search the keyword "sum of arithmetic sequence" on the Internet) directly replace the above formula, then 1 / N + 2 / N +... + (n-1) / N = [(n

1 / 2 + (1 / 3 + 2 / 3) + (1 / 4 + 2 / 4 + 3 / 4) + (1 / 5 + 2 / 5 + 3 / 5 + 4 / 5)
I want to take off the process
1 / 2 + (1 / 3 + 2 / 3) + (1 / 4 + 2 / 4 + 3 / 4) + (1 / 5 + 2 / 5 + 3 / 5 + 4 / 5) + +(one tenth + two tenths +...) +Nine tenths) how much is it?

Original formula = 1 / 2 + (1 + 2) / 3 + (1 + 2 + 3) / 4 + (1 + 2 + 3 + 4) / 5
=1/2+1+6/4+10/5
=1/2+1+3/2+2
=(1+3)/2+3=2+3=5