vault backup: 2022-09-04 13:55:28

OJ notes/pages/Leetcode Non-Overlapping-Intervals.md

@@ -70,5 +70,33 @@ first sort the intervals.
 pick the intervals with smallest end, which will allow us to
 make more room for following ones.
 
+#tip: Use `&` to reference vectors in comp.function to save 
+time.
+
 ### Solution
 
+```cpp
+class Solution {
+  static bool comp(vector<int> &a, vector<int> &b) { return a[1] < b[1]; }
+
+public:
+  int eraseOverlapIntervals(vector<vector<int>> &intervals) {
+
+    sort(intervals.begin(), intervals.end(), comp);
+
+    // Using this var to skip overlapping intervals.
+    auto before = intervals[0];
+
+    int ans = 0;
+
+    for (int i = 1, size = intervals.size(); i < size; i++) {
+      if (intervals[i][0] < before[1]) {
+        ans++;
+      } else {
+        before = intervals[i];
+      }
+    }
+
+    return ans;
+  }
+};