Create meeting-scheduler.cpp

Author: kamyu104

C++/meeting-scheduler.cpp

@@ -0,0 +1,86 @@
+// Time:  O(n) ~ O(nlogn)
+// Space: O(n)
+
+class Solution {
+public:
+    vector<int> minAvailableDuration(vector<vector<int>>& slots1, vector<vector<int>>& slots2, int duration) {
+        vector<pair<int, int>> min_heap;
+        for (const auto& slot : slots1) {
+            if (slot[1] - slot[0] >= duration) {
+                min_heap.emplace_back(slot[0], slot[1]);
+            }
+        }
+        for (const auto& slot : slots2) {
+            if (slot[1] - slot[0] >= duration) {
+                min_heap.emplace_back(slot[0], slot[1]);
+            }
+        }
+        make_heap(min_heap.begin(), min_heap.end(), greater<>());  // Time: O(n)
+        while (min_heap.size() > 1) {
+            pop_heap(min_heap.begin(), min_heap.end(), greater<>());  // Time: O(logn)
+            const auto left = min_heap.back();
+            min_heap.pop_back();
+            pop_heap(min_heap.begin(), min_heap.end(), greater<>());
+            const auto right = min_heap.back();
+            min_heap.pop_back();
+            min_heap.emplace_back(right);
+            push_heap(min_heap.begin(), min_heap.end(), greater<>());
+            if (left.second - right.first >= duration) {
+                return {right.first, right.first + duration};
+            }
+        }
+        return {};
+    }
+};
+
+// Time:  O(nlogn)
+// Space: O(n)
+class Solution2 {
+public:
+    vector<int> minAvailableDuration(vector<vector<int>>& slots1, vector<vector<int>>& slots2, int duration) {
+        priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> min_heap;
+        for (const auto& slot : slots1) {
+            if (slot[1] - slot[0] >= duration) {
+                min_heap.emplace(slot[0], slot[1]);
+            }
+        }
+        for (const auto& slot : slots2) {
+            if (slot[1] - slot[0] >= duration) {
+                min_heap.emplace(slot[0], slot[1]);
+            }
+        }
+        while (min_heap.size() > 1) {
+            const auto left = min_heap.top();
+            min_heap.pop();
+            const auto right = min_heap.top();
+            if (left.second - right.first >= duration) {
+                return {right.first, right.first + duration};
+            }
+        }
+        return {};
+    }
+};
+
+// Time:  O(nlogn)
+// Space: O(n)
+class Solution3 {
+public:
+    vector<int> minAvailableDuration(vector<vector<int>>& slots1, vector<vector<int>>& slots2, int duration) {
+        sort(slots1.begin(), slots1.end());
+        sort(slots2.begin(), slots2.end());
+        int i = 0, j = 0;
+        while (i < slots1.size() && j < slots2.size()) {
+            const auto& left = max(slots1[i][0], slots2[j][0]);
+            const auto& right = min(slots1[i][1], slots2[j][1]);
+            if (left + duration <= right) {
+                return {left, left + duration};
+            }
+            if (slots1[i][1] < slots2[j][1]) {
+                ++i;
+            } else {
+                ++j;
+            }
+        }
+        return {};
+    }
+};