面试：数组：合并区间：058

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///* * 合并区间 */import java.util.*;class Interval{    int start; //起点    int end; //终点    Interval(int a, int b){        start=a;        end=b;    }}public class MyDemo{    public  ArrayList<Interval> merge(ArrayList<Interval> intervals){        ArrayList<Interval> res=new ArrayList<Interval>();        if (intervals == null || intervals.isEmpty())            return res;        //内部定义比较器        Comparator<Interval> comparator = new Comparator<Interval>(){            public int compare(Interval a, Interval b){                if (a.start < b.start) return -1;                else if(a.start>b.start) return  1;                else{                    //start相同，比较end                    if(a.end < b.end) return -1;                    else if(a.end > b.end) return 1;                    else return 0;                }            }        };        Collections.sort(intervals,comparator);        for(int i=0;i< intervals.size();i++){            Interval current = intervals.get(i);            if(res.isEmpty())            {                res.add(current);            }else {                Interval last=res.get(res.size()-1);                if(last.end>=current.start){                    last.end=Math.max(last.end,current.end);                }else{                    res.add(current);                }            }        }        return res;    }    public static void main(String[] args){        ArrayList<Interval> testArrayList = new ArrayList<Interval>();        testArrayList.add(new Interval(1,5));        testArrayList.add(new Interval(6,10));        testArrayList.add(new Interval(4,6));        testArrayList.add(new Interval(15,20));         ArrayList<Interval> result=new  ArrayList<Interval>();         MyDemo demo=new MyDemo();         result = demo.merge (testArrayList);         for(int i=0;i<result.size();i++)         {           Interval tmpI = result.get(i);           System.out.println("["+tmpI.start+","+tmpI.end+"]");         }    }}

c++

#include <bits/stdc++.h>using namespace std;const int N = 0;struct Interval {int start;    int end;    Interval() : start(0), end(0) { }    Interval(int s, int e) : start(s), end(e) { }};class Solution {private:    vector<Interval> insert(vector<Interval> &intervals, Interval newInterval) {        auto it = intervals.begin();          auto it_head = it;                // head of erase items        while (it != intervals.end()) {            if (newInterval.end < it->start) {                it = intervals.erase(it_head, it);                intervals.insert(it, newInterval);                return intervals;            } else if (newInterval.start > it->end) {                it++;                it_head++;            } else {                newInterval.start = min(newInterval.start, it->start);                newInterval.end = max(newInterval.end, it->end);                // not erase immediately                // it = intervals.erase(it);                it++;            }        }        if (it_head != it)            it = intervals.erase(it_head, it);        intervals.insert(intervals.end(), newInterval);        return intervals;    }public:    vector<Interval> merge(vector<Interval> &intervals) {        vector<Interval> res;        for (auto &i : intervals)            insert(res, i);        return res;    }};int main() {    int a, b, n;    vector<Interval> itv;    Solution s;    cin >> n;    while (n--) {        cin >> a >> b;        itv.push_back(Interval(a, b));    }    itv = s.merge(itv);    for (auto &i : itv)        cout << i.start << ' ' << i.end << endl;    return 0;}

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