[leetcode] 56. Merge Intervals 解题报告

题目链接：

Given a collection of intervals, merge all overlapping intervals.

For example,

Given

[1,3],[2,6],[8,10],[15,18]

,

return

[1,6],[8,10],[15,18]

.

思路：要注意区间首先要排序, 然后维护一个当前的起点终点, 遍历所有的区间. 如果当前区间和我们维护的区间没有交集, 就将维护的那个区间加到结果集合中, 将其起点终点设为当前区间.

代码如下：

/**
* Definition for an interval.
* struct Interval {
*     int start;
*     int end;
*     Interval() : start(0), end(0) {}
*     Interval(int s, int e) : start(s), end(e) {}
* };
*/
class Solution {
public:
vector<Interval> merge(vector<Interval>& intervals) {
if(intervals.size() ==0) return {};
auto cmp = [](Interval a, Interval b) { return a.start < b.start; };
sort(intervals.begin(), intervals.end(), cmp);
vector<Interval> result;
int start = intervals[0].start, end = intervals[0].end;
for(int i = 1; i < intervals.size(); i++)
{
if(intervals[i].start > end)
{
result.push_back(Interval(start, end));
start = intervals[i].start, end = intervals[i].end;
continue;
}
end=max(end, intervals[i].end);
}
result.push_back(Interval(start, end));
return result;
}
};