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The code runs fine on my machine but fails to give the right answer in codeforces
By CodeRazer, history, 3 years ago, In English

The following code gives the correct result on my machine, but doesn't give the right answer on codeforces. 125707404 any help will be be appreciated

#include <stdio.h>
#include <stdlib.h>
 
int comparator (const void * p1, const void * p2)
{
  return (*(double*)p1 - *(double*)p2);
}
 
double maxx(double a, double b) {
    if (a > b){
        return a;
    }
    else{
        return b;
    }
}
 
int main() {
    int n;
    double l;
    scanf("%d %lf", &n, &l);
    double a[n+1];
    for (int i = 0; i<n; ++i) {
        scanf("%lf", &a[i]);
    }
    qsort(a, n, sizeof(double), comparator);
    double maxdiff = 0;
    double prev = a[0];
    maxdiff = (a[0] - 0)*2;
    for (int i = 1; i<n; ++i){
        maxdiff = maxx(maxdiff, a[i] - prev);
        prev = a[i];
    }
    maxdiff = maxx(maxdiff, l*2 - prev*2);
    double ans;
    ans = maxdiff/2;
 
    printf("%lf\n", ans);
    return 0;
}
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Comments Comments (2)
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3 years ago, # |
  Vote: I like it +8 Vote: I do not like it

I couldn't find any issue with the code, as it seemed to work as intended on my machine as well.
I used some printf statements to check the values of the variables after the input had been taken, and ran it on the codeforces custom invocation tab. What i observed was that the input worked fine for the G++ and clang compilers, but for "GNU GCC C11 5.1.0", there were some issues with taking inputs of type double (The printf statements showed that the entire array $$$a$$$, and the variable $$$l$$$, all of type double, were = $$$0$$$, after the input had been taken). Interestingly, there were no issues taking inputs of type float (but the problem required a greater degree of precision, so double had to be used by any means). Although I might not be correct, it might be a compiler specific issue on codeforces.

Also, when I submitted the same code using the g++17 compiler, your answer was correct and got accepted :)

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