问共享生日派对

EN

double r(){return Math.random();}

n->{int r=52,a[]=new int[r];for(;n-->0;)if(r()*364>104)++a[(int)(r()*r)];for(;++n<52;)r=r>51&a[n]>1&r()<1-5/Math.pow(5,a[n])&r()<1-Math.pow(2./3,a[n])?n:r;return r;}

double r() { return Math.random(); } // shortcut for Math.random(), saves a few bytes

n -> { // lambda taking an intger argument and returning an integer
    int r = 52, // this will hold the result; set to the value for "no Very Angry people" for now
    a[] = new int[r]; // array counting the people whose birthday lies in each week
    for(; n-- > 0; ) // for each person:
        if(r() * 364 > 104) // determine whether their birthday is on a weekday that is not the 30th of December ...
            ++a[(int) (r() * r)]; // ... only if so, increment the counter for a random ISO week
    for(; ++n < 52; ) // loop through the weeks; n is -1 before the loop
        r = r > 51   // if r is still the default ...
          & a[n] > 1 // ... and there is more than one person with a birthday that week ...
          & r() < 1 - 5/Math.pow(5, a[n]) // ... and at least two people have a different birthday ...
          &r() < 1 - Math.pow(2./3, a[n]) // ... and at least one person has the Very Angry personality type ...
          ? n  // ... set the current week as the result ...
          : r; // ... otherwise leave it the same
    return r;  // return the result
}