Create insert-interval.cpp

C++/insert-interval.cpp

@@ -0,0 +1,35 @@
+// Time:  O(n)
+// Space: O(1)
+
+/**
+ * Definition for an interval.
+ * struct Interval {
+ *     int start;
+ *     int end;
+ *     Interval() : start(0), end(0) {}
+ *     Interval(int s, int e) : start(s), end(e) {}
+ * };
+ */
+class Solution {
+public:
+    vector<Interval> insert(vector<Interval>& intervals, Interval newInterval) {
+        size_t i = 0;
+        vector<Interval> result;
+        // Insert intervals appeared before newInterval.
+        while (i < intervals.size() && newInterval.start > intervals[i].end) {
+            result.emplace_back(intervals[i++]);
+        }
+
+        // Merge intervals that overlap with newInterval.
+        while (i < intervals.size() && newInterval.end >= intervals[i].start) {
+            newInterval = {min(newInterval.start, intervals[i].start),
+                max(newInterval.end, intervals[i].end)};
+            ++i;
+        }
+        result.emplace_back(newInterval);
+
+        // Insert intervals appearing after newInterval.
+        result.insert(result.end(), intervals.cbegin() + i, intervals.cend());
+        return result;
+    }
+};