MasterRayuga's blog

Undefined Behaviour
By MasterRayuga, history, 3 years ago, In English

Can someone please tell me why my code is showing this type of undefined behavior

here is the first submission which is getting WA on test 2 (when submitted on c++17) & WA on test 5 (when submitted on c++20)

here is the accepted solution The only thing that I have changed here is

        for(int i=0;i<n;i++){
            cin>>arr[i];
            mp1[arr[i]]++;
            if(mp1[arr[i]]>=k){
                s1.insert(arr[i]);
            }
        }

to

        for(int i=0;i<n;i++){
            cin>>arr[i];
            mp1[arr[i]]++;
        }
        for(int i=0;i<n;i++){
            if(mp1[arr[i]]>=k){
                s1.insert(arr[i]);
            }            
        }
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3 years ago, # |
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comparing your both submission using codeforces' compare feature shows that you changed the upper limit of the for loop in maxiConsecutiveSubarray method

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    3 years ago, # ^ |
    ← Rev. 2   Vote: I like it 0 Vote: I do not like it

    You are right but thats not the cause if i change my for loop in maxiConsecutiveSubarray like that of my last submission its still giving me ac, link to submission, So it's not the main culprit here

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3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

The reason for the UB is 'out of bounds' on the line 40. Change j < N to j + 1 < N

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