I submitted exactly the same code for 86D - Мощный массив on different platforms. Here are the results:

• GNU C++17 : 165293098 -> 4086 ms (+0 KB)
• GNU C++17 (64): 165293845 -> 1152 ms (+4 KB)
• GNU C++20 (64): 165294370 -> 1122 ms (+8 KB)

There is a small increase in memory when using 64-bit, but the time difference is pretty huge!

Can anybody explain why?