Merge pull request #1457 from 0xff-dev/main

add problems 3701-3800

Merge pull request #1456 from 6boris/dev

update go.mod

update go.mod

Merge pull request #1406 from 0xff-dev/960

Merge pull request #1407 from 0xff-dev/3074

Merge pull request #1408 from 0xff-dev/1351

Merge pull request #1405 from 0xff-dev/955

Merge pull request #1404 from 0xff-dev/599

Merge pull request #1403 from 0xff-dev/3652

Merge pull request #1402 from 0xff-dev/3573

Merge pull request #1409 from 0xff-dev/756

Merge pull request #1410 from 0xff-dev/3668

Merge pull request #1411 from 0xff-dev/961