Create 871. Minimum Number of Refueling Stops

Author: rajatag03

871. Minimum Number of Refueling Stops

@@ -0,0 +1,45 @@
+class Solution {
+    public int minRefuelStops(int target, int startFuel, int[][] stations) {
+        int n=stations.length;
+        long[] dp = new long[n+1];
+        dp[0]=startFuel;
+        
+        for(int i=0;i<n;i++){
+            for(int refill = i;refill>=0 && dp[refill]>=stations[i][0];refill--){
+                dp[refill+1] = Math.max(dp[refill+1],dp[refill] + stations[i][1]);
+            }
+        }
+        
+        for(int i=0;i<=n;i++){
+            if(dp[i]>=target){
+                return i;
+            }
+        }
+        
+        return -1;
+    }
+}
+
+class Solution {
+    public int minRefuelStops(int target, int startFuel, int[][] stations) {
+        int n=stations.length;
+       PriorityQueue<int[]> pq= new PriorityQueue<>((a,b) -> b[1]-a[1]);
+        
+        int refill =0,i=0;
+        int distance = startFuel;
+        
+        while(distance<target){
+            while(i<n && distance >= stations[i][0]){
+                pq.offer(stations[i]);
+                i++;
+            }
+            
+            if(pq.isEmpty()) return -1;
+            
+            distance += pq.remove()[1];
+            refill++;
+        }
+        
+        return refill;
+    }
+}