_436.java

package com.fishercoder.solutions;

import com.fishercoder.common.classes.Interval;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;


public class _436 {

    public static int[] findRightInterval(Interval[] intervals) {
        if (intervals == null || intervals.length == 0) {
            return new int[0];
        }
        int[] result = new int[intervals.length];
        result[0] = -1;
        Interval last = intervals[intervals.length - 1];
        Interval first = intervals[0];
        Map<Interval, Integer> map = new HashMap();
        for (int i = 0; i < intervals.length; i++) {
            map.put(intervals[i], i);
        }

        Collections.sort(Arrays.asList(intervals), (o1, o2) -> o1.start - o2.start);

        for (int i = 1; i < intervals.length; i++) {
            //TODO: use binary search for the minimum start interval for interval[i-1] instead of a while loop
            int tmp = i - 1;
            int tmpI = i;
            while (tmpI < intervals.length && intervals[tmpI].start < intervals[tmp].end) {
                tmpI++;
            }
            if (tmpI < intervals.length) {
                result[map.get(intervals[tmp])] = map.get(intervals[tmpI]);
            } else {
                result[map.get(intervals[tmp])] = -1;
            }
        }
        if (result[intervals.length - 1] == 0 && last.end > first.start) {
            result[intervals.length - 1] = -1;
        }
        return result;
    }


    public static void main(String... args) {
        Interval[] intervals = new Interval[3];
//        intervals[0] = new Interval(1,4);
//        intervals[1] = new Interval(2,3);
//        intervals[2] = new Interval(3,4);

        intervals[0] = new Interval(3, 4);
        intervals[1] = new Interval(2, 3);
        intervals[2] = new Interval(1, 2);
        findRightInterval(intervals);
    }
}