Update 2054.Two-Best-Non-Overlapping-Events.cpp

Author: wisdompeak

Greedy/2054.Two-Best-Non-Overlapping-Events/2054.Two-Best-Non-Overlapping-Events.cpp

@@ -3,33 +3,38 @@ class Solution {
  {
  return a[1] < b[1];
  }
+
 public:
  int maxTwoEvents(vector<vector<int>>& events) 
  {
  int n = events.size();
  sort(events.begin(), events.end(), cmp);
 
- vector<pair<int,int>>dp; // {time, value}
- dp.push_back({events[0][1], events[0][2]});
- int rollingMax = events[0][2];
- 
- int ret = events[0][2];
+ vector<int>rollingMax(n);
+ int m = 0;
+ for (int i=0; i<n; i++)
+ {
+ m = max(m, events[i][2]);
+ rollingMax[i] = m;
+ }
+ 
+ vector<int>endTimes;
+ int ret = 0;
 
- for (int i=1; i<n; i++)
+ for (int i=0; i<n; i++)
  {
  int a = events[i][0]-1, b = events[i][1], v = events[i][2];
+ ret = max(ret, v);
 
- int lastMax = 0;
- auto iter = upper_bound(dp.begin(), dp.end(), make_pair(a, INT_MAX));
- if (iter!=dp.begin())
+ auto iter = upper_bound(endTimes.begin(), endTimes.end(), a);
+ if (iter!=endTimes.begin())
  {
  iter = prev(iter);
- lastMax = iter->second;
- }  
- ret = max(ret, lastMax + v);
+ int idx = iter - endTimes.begin();
+ ret = max(ret, rollingMax[idx] + v);
+ }
 
- rollingMax = max(rollingMax, v);
- dp.push_back({b, rollingMax});
+ endTimes.push_back(b);
  }
 
  return ret;