Given a collection of intervals, merge all overlapping intervals.
Example 1:
Input: [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]
Explanation: Since intervals [1,3] and [2,6] overlaps, merge them into [1,6].
Example 2:
Input: [[1,4],[4,5]]
Output: [[1,5]]
Explanation: Intervals [1,4] and [4,5] are considered overlapping.
# input:
[[1,3],[2,6],[8,10],[15,18]]
[[1,4],[4,5]]
[[1,4],[2,3]]
[[2,3],[4,5],[6,7],[8,9],[1,10]]
[[3,3],[0,1],[0,0]]
# output:
[[1,6],[8,10],[15,18]]
[[1,5]]
[[1,4]]
[[1,10]]
[[0,1],[3,3]]
先对输入排序,使用C++比较器格式:
vector<vector<int>> merge(vector<vector<int>>& intervals) {
if(intervals.empty())
return {};
vector<vector<int>>res;
//keypoint
sort(begin(intervals), end(intervals),
[](vector<int> a, vector<int> b){return a[0]<b[0];});
//法1
int head=intervals[0][0],end=intervals[0][1];
for(int i=1;i<intervals.size();i++){
if(end<intervals[i][0]){
res.push_back({head,end});
head=intervals[i][0];
}
if(end<intervals[i][1])
end=intervals[i][1];
}
res.push_back({head,end});
/*法二
res.push_back(intervals[0]);
for(int i=1;i<intervals.size();i++){
if(res.back()[1]<intervals[i][0]){
res.push_back(intervals[i]);
}
else if(res.back()[1]<intervals[i][1]){
res.back()[1]=intervals[i][1];
}
}
*/
return res;
}
Python:
def merge(self, intervals: List[List[int]]) -> List[List[int]]:
if len(intervals)==0: return []
intervals=sorted(intervals,key=lambda x : x[0])
res=[intervals[0]]
for n in intervals[1:]:
if n[0] <= res[-1][1]:
res[-1][1]=max(n[1],res[-1][1])
else:
res.append(n)
return res