CareerCup

The last line should be

return [max(a,c), min(b,d)]

with JavaScript (you can copy it into your browser console (F12) to try it out)

// some ranges
var intRangeA = [10, 100];
var intRangeB = [60, 150];
var intRangeC = [120, 200];
var intRangeD = [170, 200];
var ranges = [intRangeA, intRangeB, intRangeC, intRangeD];
// sort function
var numSort = function(a, b) {
	return b - a;
};
// loop over ranges
for (var i = 0; i < ranges.length; i++) {
	for (var j = 0; j < ranges.length; j++) {
		if (i != j) {
			var sortA = ranges[i].sort(numSort);
			var sortB = ranges[j].sort(numSort);

			var maxA = sortA[0];
			var minA = sortA[sortA.length - 1];
			var maxB = sortB[0];
			var minB = sortB[sortB.length - 1];

			if (minA <= minB && maxA <= maxB) {
				var diff = maxA - minB;
				if (diff > -1) {
					console.debug("Overlap found([" + ranges[i].sort(numSort).reverse() + "];[" + ranges[j].sort(numSort).reverse() + "]), with overlapping range:" + minB + ";" + maxA);
				}
			}

		}
	}
}

Interger ranges (x1,x2) and (y1,y2)

int overlap(int x1,int x2,int y1,int y2){
	if(x2>=y1 && x1<=y2)
		return ((Math.max(x2,y2) - Math.min(x1,y1))-(Math.abs((x2-y1)-(y2-x1)));
	else
		return -1;
}

check if 2 ranges [a,b] and [c,d] overlap

if (b < c || d < a) 
    return emtpy;
    
return [min(a,c), min(b,d)]