src/main/java/com/conveyal/gtfs/util/Deduplicator.java
public int[] deduplicateIntArray(int[] original) {
        if (original == null) return null;
        IntArray intArray = new IntArray(original);
        IntArray canonical = canonicalIntArrays.get(intArray);
        if (canonical == null) {
            canonical = intArray;
            canonicalIntArrays.put(canonical, canonical);
        }
        return canonical.array;
    }
public int[] deduplicateIntArray(int[] original) {
        if (original == null) return null;
        IntArray intArray = new IntArray(original);
        IntArray canonical = canonicalIntArrays.get(intArray);
        if (canonical == null) {
            canonical = intArray;
            canonicalIntArrays.put(canonical, canonical);
        }
        return canonical.array;
    }
Used to deduplicate time and stop sequence arrays. The same times may occur in many trips.