Auto comment: topic has been updated by Ahmed-Nawaz (previous revision, new revision, compare).

no da den

I have had to switch to 32bit int only once or twice (never on codeforces). One of the times it was for some cses dp problem with very tight limits

I have done problems where using long long everywhere will lead to TLE (specifically: https://usaco.org/index.php?page=viewproblem2&cpid=1207)

Just use 32bit numbers unless the problem statement shows you that values would be large or you are computing products of large numbers.

MLE is situational, just check if (array size) * 8 bytes instead of 4 comfortably fits in the limit. Most problems do not care too much about memory.

For time, I ran some benchmarks for you. This is on GCC with -O2 on my i7-10700k.

• 300M Adds: 0.42s vs 0.42s
• 300M Multiplys (actually multiply-then-increment): 0.61-0.63s vs 0.61-0.62s
• 300M Divides: 0.42-0.44s vs 0.42-0.44s (yes, divides are supposed to be slower, but the loop I have testing them is not the greatest)

Basically there's no difference in 32 vs 64 bits because they all probably execute exactly the same in the ALU.

(Bad) code: https://github.com/greatericontop/CompetitiveProgrammingStash/blob/main/random/benchmark.cpp

I tested again with a small loop written fully in assembly, 1 billion additions run in 0.20-0.21s vs 0.20-0.21s again.

Code: https://github.com/greatericontop/CompetitiveProgrammingStash/blob/main/random/benchmark_assembly.s (revised version to reduce the effect of pipelining)

I have encountered a similar situation before. There was a problem where I use long long in a dp array that did not require long long, resulting in TLE. After changing it to int, it passed.

i solved one questions i dont really remember the rating and problem statment ,as much i remember it was 1400 rated problem where i came up with almost 1e7 time compexity solution ,it was getting TLE repeatedly and as mush as i can think it was a solution which cant be optimized further , i just thought why not switch from long long to int and surprisingly it passed the all test cases , from that day i get so scared to use long long . if i find the problem , i will update.

I mostly use int64_t in my codes. TLE/MLE often occur in problems with strict constraints. Sometimes I put #define int64_t int32_t at the start of my codes.

I use #define int long long in most of my code, and it's really effective as I rarely see Wrong Answers due to overflow. However, it's not harmful; if possible, I still recommend thinking carefully before setting a variable to int64 or int32, as they have their own advantages.

Happened to me couple of times with some DP problems , got MLE using ll = long long; then changed it to int and passed peacefully.

many times, especially in Macedonian national contests where the TL and ML limits are tight due to limitations of the judging system