1642. Furthest Building You Can Reach

class Solution {
    public int furthestBuilding(int[] heights, int bricks, int ladders) {
        PriorityQueue<Integer> pq = new PriorityQueue<>();
        for(int i = 1; i < heights.length; i++) {
            int diff = heights[i] - heights[i-1];
            if(diff > 0) {
                if(pq.size() < ladders) {
                    pq.offer(diff);
                }
                else {
                    int br = diff;
                    //Optimize previous ladder use
                    if(pq.size() > 0 && pq.peek() < diff) {
                        br = pq.remove();
                        pq.offer(diff);
                    }
                    if(bricks-br >= 0) {
                        bricks-=br;
                    }
                    else {
                        return i-1;
                    }
                }
            }
        }
        
        return heights.length-1;
    }
}

class Solution {
    public int furthestBuilding(int[] heights, int bricks, int ladders) {
        int n=heights.length;
        PriorityQueue<Integer> q= new PriorityQueue<>();
        int brickesUsed=0;
        for(int i=1;i<n;i++){
            int diff= heights[i] - heights[i-1];
            if(diff>0){
                q.add(diff);
                if(q.size()>ladders){
                    brickesUsed+=q.remove();
                }
                
                if(brickesUsed>bricks){
                    return i-1;
                }
            }
        }
        return n-1;
    }
}