给定两个排序后的区间序列，序列内每个区间两两互不相交，返回两个序列相交的区间的下标
- 1<=len(a),len(b)<=1e5
- abs(max(a))<=1e9
样例
输入: a = [[0,3], [7,10]] , b = [[-1,1],[2,8]]
输出: ans = [[0,0],[0,1],[1,1]]
bool is_intersected(const vector<int> &l, const vector<int> &r) {
if(l[0] == r[0])
return true;
else if(l[0] < r[0])
return r[0] <= l[1];
else
return l[0] <= r[1];
}
vector<vector<int>> Intersection(vector<vector<int>> &a, vector<vector<int>> &b) {
vector<vector<int>> res;
if(a.empty() || b.empty())
return res;
for(int i = 0, j = 0; i < a.size() && j < b.size();) {
if(is_intersected(a[i], b[j]))
res.emplace_back(vector<int>({ i, j }));
if(a[i][1] == b[j][1]) {
++i;
++j;
} else if(a[i][1] > b[j][1])
++j;
else
++i;
}
return res;
}