Misc Solution: Pre-School Math Problem
This problem can be solved by pre-school children in 5-10 minutes, by programer - in 1 hour, by people with higher education... well, check it yourself! :)
8809=6
7111=0
2172=0
6666=4
1111=0
3213=0
7662=2
9313=1
0000=4
2222=0
3333=0
5555=0
8193=3
8096=5
7777=0
9999=4
7756=1
6855=3
9881=5
5531=0
2581=?
Solution
I leave it to you to find the rule. But as I call me a programmer, here is my 1 hour solution:
function solution(n) { var cnt = [ 1,0,0,0,1,0,1,0,2,1]; var s = 0; while (n > 0) { s+= cnt[n % 10]; n = n / 10 | 0; } return s; } solution(2581);