Create 253.cpp

LeetCode-CN/253.cpp

@@ -0,0 +1,34 @@
+class Solution {
+public:
+    int minMeetingRooms(vector<vector<int>>& intervals) {
+        vector<int> starts, ends;
+        for (auto& vec : intervals) {
+            starts.push_back(vec[0]);
+            ends.push_back(vec[1]);
+        }
+        sort(starts.begin(), starts.end());
+        sort(ends.begin(), ends.end());
+
+        int needRoom = 0;
+        int maxRoom = 0;
+        for (int i = 0, j = 0; i < starts.size() && j < ends.size();) {
+            if (starts[i] < ends[j]) {
+                needRoom++;
+                maxRoom = max(maxRoom, needRoom);
+                i++;
+                continue;
+            }
+
+            if (starts[i] > ends[j]) {
+                needRoom--;
+                j++;
+                continue;
+            }
+
+            i++;
+            j++;
+        }
+
+        return maxRoom;
+    }
+};