10801 - Lift Hopping

/*10801 - Lift Hopping
 * 以每一層樓爲頂點，每個電梯可以到達的兩層樓之間的秒數爲每一條邊的權值，
 * 以此構建一個無向圖。然後利用dijkstra求出最短的時間，
 * 注意每次換乘電梯需要等待60s（注意初始定點不需要60s的等待）。*/
import java.util.Arrays;
import java.util.Scanner;

class Main {
	static final int INF = 100000;
	static final int MAXN = 105;
	static final int MAXS = 10;
	static int[] speed = new int[MAXS];
	static int[] floors = new int[MAXN];
	static int[] d = new int[MAXN];
	static int[][] w = new int[MAXN][MAXN];
	static int[] vis = new int[MAXN];
	static int n, k;
	static int num;

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		while (scanner.hasNext()) {
			String s = scanner.nextLine();
			String[] ss = s.split(" ");
			n = Integer.parseInt(ss[0]);
			k = Integer.parseInt(ss[1]);
			for (int i = 0; i < MAXN; i++) {
				Arrays.fill(w[i], INF);
			}
			s = scanner.nextLine();
			ss = s.split(" ");
			for (int i = 1; i <= n; i++) {
				speed[i] = Integer.parseInt(ss[i - 1]);
			}
			for (int i = 1; i <= n; i++) {
				num = 0;
				s = scanner.nextLine();
				ss = s.split(" ");
				for (num = 0; num < ss.length; num++)
					floors[num] = Integer.parseInt(ss[num]);
				build_graph(i);
			}
			if (k == 0) {
				System.out.println(0);
				continue;
			}
			dijkstra();
		}
	}

	private static void build_graph(int s) {// 構造無向圖
		for (int i = 0; i < num; i++) {
			for (int j = i + 1; j < num; j++) {
				int dis = Math.abs(floors[i] - floors[j]) * speed[s];//權值計算
				if (w[floors[i]][floors[j]] > dis)//更新
					w[floors[i]][floors[j]] = w[floors[j]][floors[i]] = dis;
			}
		}
	}

	private static void dijkstra() {
		Arrays.fill(vis, 0);
		Arrays.fill(d, INF);
		d[0] = 0;
		for (int i = 0; i < MAXN; i++) {
			int x = 0, m = INF;
			for (int y = 0; y < MAXN; y++) {// 找到還未標記的節點中d值最小的節點x
				if (vis[y] == 0 && d[y] <= m)
					m = d[x = y];
			}
			vis[x] = 1;// 標記
			for (int y = 0; y < MAXN; y++) {// 更新從x出發的所有邊
				d[y] = Math.min(d[y], d[x] + w[x][y] + 60);
			}
		}
		if (d[k] == INF) {
			System.out.println("IMPOSSIBLE");
		} else {
			System.out.println(d[k] - 60);//注意減去60
		}
	}
}