LC 986. Interval List Intersections

Posted 2021-02-07 ethanhong

Given two lists of closed intervals, each list of intervals is pairwise disjoint and in sorted order.

Return the intersection of these two interval lists.

(Formally, a closed interval [a, b] (with a <= b) denotes the set of real numbers x with a <= x <= b.  The intersection of two closed intervals is a set of real numbers that is either empty, or can be represented as a closed interval.  For example, the intersection of [1, 3] and [2, 4] is [2, 3].)

 

 

class Solution {
public:
  vector<Interval> intervalIntersection(vector<Interval>& A, vector<Interval>& B) {
    int ai = 0, bi = 0;
    vector<Interval> ret;
    while(ai < A.size() && bi < B.size()) {
      if(A[ai].end < B[bi].start) {
        ai++;
        continue;
      } else if(B[bi].end < A[ai].start) {
        bi++;
        continue;
      }
      ret.push_back(Interval(max(A[ai].start, B[bi].start), min(A[ai].end, B[bi].end)));
      if(A[ai].end <= B[bi].end) {
        ai++;
      }else{
        bi++;
      }
    }
    return ret;
  }
};