arjun_9426's blog

comparison functions and classes/structs
By arjun_9426, history, 6 years ago, In English

hello friend, i suffer a lot because of comparison functions and classes for sorting and STL data structures please help me in clearing this

comparison functions ex-> (1).when i try to sort using comparison function like->https://ideone.com/owtUzJ here problem comes when i try to sort according to my wish (2). sometimes even vectors of simple numbers give TLE or runtime error when i try to sort them using comparision function eg->https://ideone.com/FhzWw2

classes and structs https://ideone.com/FhzWw2 in this case it reinsert the value???

https://ideone.com/0POMaG in this case it reinsert the key value pair instead of just updating it???

https://ideone.com/Ae2DMR(another example where entry repeats)

please help me in this, i have suffered a lot because of this, recent one is (1)https://codeforces.me/contest/1082/submission/47244078(runtime error) (2)https://codeforces.me/contest/1082/submission/47244104(accepted) both codes are exactly same, i have just managed the comparison function benefits through extra code in 2nd one.

please somebody tell if there is any other way to use these functions/structs more effectively, else what and how we can use them . please somebody help

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6 years ago, # |
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Your compare functions need to follow string weak ordering. To sort in reverse you should use a > b and not a >= b.

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    6 years ago, # ^ |
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    thank sir, if in map/set if the compared item becomes equals what happens then(according to my verification it is leaving the other one from set/map) do i need to tell specifically when i need those entries?

    eg-> return a>b (it return false when a==b or a<b but both cases behaves different , in first it leave the second one, in second it considers and do swap)

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