D. Vanya and Treasure Codeforces Round #355 (Div. 2)

http://codeforces.com/contest/677/problem/D

建颗新树，节点元素包含r、c、dis，第i层包含拥有编号为i的钥匙的所有节点。用i-1层更新i层，逐层更新到底层。

不使用就会超时的优化：用i-1层更新时不是所有节点都有必要用到，我们对i-1层排序，取前600节点更新下层。

public class Main {
    private static final int c = 330,INF=Integer.MAX_VALUE/2,maxn=c*c*c+100,maxe=maxn*6;
    static class Node implements Comparable<Node>{
        int x,y, dis;

        public Node(int x, int y, int dis) {
            this.x = x;
            this.y = y;
            this.dis = dis;
        }

        @Override
        public int compareTo(Node o) {
            return dis -o.dis;
        }
    }
    public static void main(String[] args) {
        IO io=new IO();
        int n=io.nextInt(),m=io.nextInt(),p=io.nextInt();

        ArrayList<Node>[]al=new ArrayList[p+1];
        for (int i = 0; i < al.length; i++) al[i]=new ArrayList<>(c);
        int[]dis=new int[c*c];
        Arrays.fill(dis,INF);

        for (int i=1;i<=n;i++)for (int j=1;j<=m;j++)al[io.nextInt()].add(new Node(i,j,INF));
        al[0].add(new Node(1,1,0));

        int ans=INF;
        for (int i=1;i<=p;i++){
            Collections.sort(al[i-1]);
            for (int j=0;j<Math.min(al[i-1].size(),330);j++)for (Node k:al[i]){
                k.dis=Math.min(k.dis,al[i-1].get(j).dis+Math.abs(k.x-al[i-1].get(j).x)+Math.abs(k.y-al[i-1].get(j).y));
                if (i==p)ans=Math.min(k.dis,ans);
            }
        }
        io.println(ans);
    }
}