Update 1066.Campus-Bikes-II.cpp

Author: wisdompeak

BFS/1066.Campus-Bikes-II/1066.Campus-Bikes-II.cpp

@@ -1,44 +1,46 @@
+typedef pair<int,int> PII;
+
 class Solution {
+ int dist[10][10];
+ int visited[1024];
 public:
- int dis(vector<vector<int>>& workers, vector<vector<int>>& bikes, int i, int j)
- {
- int x1=workers[i][0];
- int y1=workers[i][1];
- int x2=bikes[j][0];
- int y2=bikes[j][1];
- return abs(x1-x2)+abs(y1-y2);
- }
- 
- 
  int assignBikes(vector<vector<int>>& workers, vector<vector<int>>& bikes) 
  {
- set<vector<int>>Set;
- Set.insert({0,0,0});
+ int m = workers.size();
+ int n = bikes.size();
+ for (int i=0; i<m; i++)
+ for (int j=0; j<n; j++)
+ {
+ int x1=workers[i][0];
+ int y1=workers[i][1];
+ int x2=bikes[j][0];
+ int y2=bikes[j][1];
+ dist[i][j] = abs(x1-x2)+abs(y1-y2);
+ }
 
- set<vector<int>>visited;
+ priority_queue<PII, vector<PII>, greater<>>pq; 
+ pq.push({0, 0}); 
 
- while (true)
+ while (!pq.empty())
  {
- int cost = (*Set.begin())[0];
- int i = (*Set.begin())[1];
- int taken = (*Set.begin())[2];
- Set.erase(Set.begin());
- 
- if (i==workers.size())
- return cost;
- 
- if (visited.find({i,taken})!=visited.end())
- continue;
- visited.insert({i,taken});
+ auto [cost, state] = pq.top();
+ pq.pop();
+ 
+ if (visited[state]) continue;
+ visited[state] = 1;
 
+ int i = __builtin_popcount(state);
+ if (i==m) return cost;
+ 
  for (int j=0; j<bikes.size(); j++)
  {
- if ((taken&(1<<j)) !=0)
- continue;
- Set.insert({cost+dis(workers, bikes, i,j), i+1, taken+(1<<j)});
- } 
+ if ((state>>j)&1) continue;
+ int newState = state+(1<<j);
+ if (visited[newState]) continue; 
+ pq.push({cost+dist[i][j], newState});
+ }
  }
- 
+  
  return 0;
  }
 };