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| bool mySort(vector<int>& a, vector<int>& b)
{
return a[0] < b[0];
}
class Solution {
public:
vector<vector<int>> merge(vector<vector<int>>& intervals) {
vector<int> re;
sort(intervals.begin(), intervals.end(), mySort);
re.push_back(intervals[0][0]);
re.push_back(intervals[0][1]);
int index = 2;
for(auto i = intervals.begin() + 1; i != intervals.end(); ++i)
{
if((*i)[0] <= re[index - 1])
re[index - 1] = max(re[index - 1], (*i)[1]);
else
{
re.push_back((*i)[0]);
re.push_back((*i)[1]);
index += 2;
}
}
vector<vector<int>> ret;
for(int i = 0; i < re.size(); i += 2)
{
ret.push_back({re[i], re[i + 1]});
}
return ret;
}
};
|
T(n) : O(nlogn)
S(n) : O(n)
同样思路的一个Solution
空间和时间占用更少
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| class Solution {
public:
vector<vector<int>> merge(vector<vector<int>>& intervals) {
sort(intervals.begin(), intervals.end());
vector<vector<int>> ret;
for(auto& interval : intervals)
{
if(ret.empty() || interval[0] > ret.back()[1])
ret.push_back(interval);
else
ret.back()[1] = max(interval[1], ret.back()[1]);
}
return ret;
}
};
|