56. Merge Intervals

Posted on | In , |

题目

https://leetcode.com/problems/merge-intervals/description/

-w948

想法

先排序，按照第一个数升序
挨个看是否可以合并
这样真的可以嘛，感觉好简单的样子，与赞数不符啊

咦，还真这样AC了，这水题，为什么900+的赞，不懂不懂

答案

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
static const auto ____ = [](){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    return nullptr;
}();
class Solution {
public:
    vector<Interval> merge(vector<Interval>& intervals) {
        vector<Interval> res;
        if (intervals.empty())
            return res;
        sort(intervals.begin(), intervals.end(), [](Interval& a, Interval& b) {
            return a.start < b.start;
        });
        res.push_back(intervals[0]);
        for (int i = 1; i < intervals.size(); i++) {
            Interval& last = res[res.size() - 1];
            if (intervals[i].start <= last.end) {
                last.end = max(last.end, intervals[i].end);
            } else {
                res.push_back(intervals[i]);
            }
        }
        return res;
    }
};