LeetCode 986. 区间列表的交集

输入：A = [[0,2],[5,10],[13,23],[24,25]], B = [[1,5],[8,12],[15,24],[25,26]]
输出：[[1,2],[5,5],[8,10],[15,23],[24,24],[25,25]]
注意：输入和所需的输出都是区间对象组成的列表，而不是数组或列表。
 

提示：

0 <= A.length < 1000
0 <= B.length < 1000
0 <= A[i].start, A[i].end, B[i].start, B[i].end < 10^9

class Solution {
public:
    vector<vector<int>> intervalIntersection(vector<vector<int>>& A, vector<vector<int>>& B) {
        if(A.empty() || B.empty())
            return {};
        int i = 0, j = 0, left, right;
        vector<vector<int>> ans;
        while(i < A.size() && j < B.size())
        {
            left = max(A[i][0], B[j][0]);
            right = min(A[i][1], B[j][1]);
            if(A[i][0] > B[j][0])
            {
                if(A[i][1] <= B[j][1])
                    ++i;
                else
                    ++j;
                if(left <= right)
                    ans.push_back({left,right});
            }
            else if(A[i][0] < B[j][0])
            {
                if(A[i][1] >= B[j][1])
                    ++j;
                else
                    ++i;
                if(left <= right)
                    ans.push_back({left,right});
            }
            else//A[i][0] == B[j][0]
            {
                if(A[i][1] < B[j][1])
                    ++i;
                else if(A[i][1] > B[j][1])
                    ++j;
                else
                    ++i, ++j;
                ans.push_back({left,right});
            }
        }
        return ans;
    }
};