How To Find Time Conflicts

pmcnally

I am working on a class scheduler, and I am having trouble figuring out how to solve the problems of deciding if a class is conflicting with one another.

Say I have 2 classes
Class 1 runs from 14:00 to 15:15
Class 2 runs from 15:00 to 15:50

Those class times are definately overlapping. Can anybody help me figure out how to tell if they are over lapping?

Here's another set of test data that is eluding me:
Class 1 runs from 18:00 to 21:00
Class 2 runs from 19:00 to 19:50

If anybody could help me out, that would be really great and much appreciated =)

-Pat

sneakyimp

suppose each class is described by an array...I'll use a super simple scheme here....

$class1['start'] = 1400;
$class1['end'] = 1515;

$class2['start'] = 1500;
$class2['end'] = 1550;

this function will help you find conflicts

function is_conflict($class1, $class2) {
   if (($class2['start'] >= $class1['start']) && 
        ($class2['start'] < $class1['end'])) {

  // conflict!
  return true;
   } else if (($class2['end'] > $class1['start']) && 
        ($class2['end'] <= $class1['end'])) {

  // conflict!
  return true;
   } else {
      return false;
   }
} // is_conflict()

that might not be perfect, but i believe it would work for a statement like this:

if (is_conflict($class1, $class2)) {
   echo "rats!  i have a conflict!";
}

sneakyimp

actually, i think i neglected a third possibility which is that one class starts AND ends while the other class is going on....not sure i got that one.

drawmack

When we wrote a class scheduler at the uni we found conflicts by defining a person's schedule in a table split into fifteen minute blocks from 7am until 10pm (my uni's class day) then a class would turn the values in the cells from 0 to 1, then if another class conflicted it was really easy, just check if any of its cells are 1.