题解 | #合并区间#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        List<Scope> inScopeList = new ArrayList<Scope>();

        //根据输入的数据获取所有区间
        while (scanner.hasNext()) {
            String str = scanner.next();
            String[] strArr = str.split(",");
            int x = Integer.parseInt(strArr[0]);
            int y = Integer.parseInt(strArr[1]);
            if (0 <= x && x <= y) {
                inScopeList.add(new Scope(x, y));
            }
        }

        //遍历区间集合，获取合并区间
        List<Scope> outScopeList = new ArrayList<Scope>();
        outScopeList.add(inScopeList.get(0));
        for (int i=0; i+1 < inScopeList.size(); i++) {
            //逐条合并
            commonScopeList(outScopeList, inScopeList.get(i+1));
        }

        //给输出的合并区间排序
        Map map = new HashMap();
        List list = new ArrayList();
        for (int i=0; i < outScopeList.size(); i++) {
            Scope scope = outScopeList.get(i);
            map.put(scope.x, scope);
            list.add(scope.x);
        }
        Collections.sort(list);

        //打印合并区间
        String outStr = "";
        for (int i=0; i < list.size(); i++) {
            Scope scope = (Scope) map.get(list.get(i));
            outStr = outStr + scope.x + "," + scope.y + " ";
        }

        System.out.println(outStr.trim());
    }

    public static void commonScopeList(List<Scope> outScopeList, Scope s) {
        for (int i=0; i < outScopeList.size(); i++) {
            Scope s1 = outScopeList.get(i);

            //如果当前两个区间有交集，则重新初始化输入参数，再从头开始比较
            if ((s1.x <= s.y && s1.y >= s.x) || (s.x <= s1.y && s.y >= s1.x)) {
                outScopeList.remove(i);
                i=-1;
                s = new Scope(minInt(s1.x, s.x), maxInt(s1.y, s.y));
            }
        }

        outScopeList.add(s);
    }

    public static int minInt(int x1, int x2) {
        return x1 < x2 ? x1 : x2;
    }

    public static int maxInt(int y1, int y2) {
        return y1 > y2 ? y1 : y2;
    }
}

class Scope {
    int x;
    int y;

    Scope(int x, int y) {
        this.x = x;
        this.y = y;
    }
}