Collect More Jewels
Time Limit: 2000/1000 MS (java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 7334 Accepted Submission(s): 1705
PRoblem Description It is written in the Book of The Lady: After the Creation, the cruel god Moloch rebelled against the authority of Marduk the Creator.Moloch stole from Marduk the most powerful of all the artifacts of the gods, the Amulet of Yendor, and he hid it in the dark cavities of Gehennom, the Under World, where he now lurks, and bides his time.
Your goddess The Lady seeks to possess the Amulet, and with it to gain deserved ascendance over the other gods.
You, a newly trained Rambler, have been heralded from birth as the instrument of The Lady. You are destined to recover the Amulet for your deity, or die in the attempt. Your hour of destiny has come. For the sake of us all: Go bravely with The Lady!
If you have ever played the computer game NETHACK, you must be familiar with the quotes above. If you have never heard of it, do not worry. You will learn it (and love it) soon.
In this problem, you, the adventurer, are in a dangerous dungeon. You are informed that the dungeon is going to collapse. You must find the exit stairs within given time. However, you do not want to leave the dungeon empty handed. There are lots of rare jewels in the dungeon. Try collecting some of them before you leave. Some of the jewels are cheaper and some are more expensive. So you will try your best to maximize your collection, more importantly, leave the dungeon in time.
Input Standard input will contain multiple test cases. The first line of the input is a single integer T (1 <= T <= 10) which is the number of test cases. T test cases follow, each preceded by a single blank line.
The first line of each test case contains four integers W (1 <= W <= 50), H (1 <= H <= 50), L (1 <= L <= 1,000,000) and M (1 <= M <= 10). The dungeon is a rectangle area W block wide and H block high. L is the time limit, by which you need to reach the exit. You can move to one of the adjacent blocks up, down, left and right in each time unit, as long as the target block is inside the dungeon and is not a wall. Time starts at 1 when the game begins. M is the number of jewels in the dungeon. Jewels will be collected once the adventurer is in that block. This does not cost extra time.
The next line contains M integers，which are the values of the jewels.
The next H lines will contain W characters each. They represent the dungeon map in the following notation:
[*] marks a wall, into which you can not move; [.] marks an empty space, into which you can move; [@] marks the initial position of the adventurer; [<] marks the exit stairs; [A] - [J] marks the jewels.
Output Results should be directed to standard output. Start each case with “Case #:” on a single line, where # is the case number starting from 1. Two consecutive cases should be separated by a single blank line. No blank line should be produced after the last test case.
If the adventurer can make it to the exit stairs in the time limit, print the sentence “The best score is S.”, where S is the maximum value of the jewels he can collect along the way; otherwise print the Word “Impossible” on a single line.
Sample Input 3
4 4 2 2 100 200
@A B<
4 4 1 2 100 200
@A B<
12 5 13 2 100 200
B……… .***.* @…A….<
Sample Output Case 1: The best score is 200.
Case 2: Impossible
Case 3: The best score is 300.
一個迷宮，L時間后倒塌，里面有M個寶藏。問能否逃出，如果逃出，得到的最大價值是多少？ 寶藏由大寫字母【A】~【J】表示，‘*’表示墻，‘.’表示路，‘@’表示起點，‘<’表示出口。 題解： 寶藏最多十個，可以bfs找出寶藏，起點，出口相互之間的最短距離，然后dfs搜索最大能獲得的價值。 剪枝：ans==Max，已經搜到獲得最大價值 代碼：
#include <iostream>#include <string>#include <cstring>#include <cstdio>#include <cmath>#include <cstdlib>#include <algorithm>#include <queue>#include <map>#define MST(s,q) memset(s,q,sizeof(s))#define INF 0x3f3f3f3f#define MAXN 9999using namespace std;struct Node{ int x, y; int sum;} s, u, v;int W, H, L, M, ans, Max; // Max保存所有寶藏價值的和char Map[100][100];int move_x[4] = {1, -1, 0, 0}, move_y[4] = {0, 0, 1, -1};int value[11];int path[20][20]; // 保存（起點，終點，各寶藏 ） 它們直接的最短距離，最多bfs地圖十幾次bool vis[100][100];bool visited[20];// 求kind到其他點的距離void bfs(int x, int y, int kind) // kind==0 表示起點，kind==M+1表示終點，1-M表示寶藏{ queue<Node> Q; s.x = x, s.y = y, s.sum = 0; MST(vis, 0); Q.push(s); vis[x][y] = 1; while (!Q.empty()) { u = Q.front(); Q.pop(); for (int i = 0; i < 4; i++) { v.x = u.x + move_x[i], v.y = u.y + move_y[i]; if (v.x >= 0 && v.x < H && v.y >= 0 && v.y < W && !vis[v.x][v.y] && Map[v.x][v.y] != '*') { vis[v.x][v.y] = 1; v.sum = u.sum + 1; if (Map[v.x][v.y] != '.') { if (Map[v.x][v.y] == '@') path[kind][0] = v.sum; else if (Map[v.x][v.y] == '<') path[kind][M + 1] = v.sum; else path[kind][Map[v.x][v.y] - 'A' + 1] = v.sum; } Q.push(v); } } }}// kind表示當前節點，time表花費的時間，V表價值void dfs(int kind , int time, int V) // kind==0 表示起點，kind==M+1表示終點，其他表示寶藏{ if (time > L || ans == Max) return; // 超出時間或已經得到最大價值 if (kind == M + 1) { ans = max(ans, V); return; } for (int i = 1; i <= M + 1; i++) { if (!visited[i]) { visited[i] = 1; dfs(i, time + path[kind][i], V + value[i - 1]); visited[i] = 0; } }}int main(){ int T, sx, sy, icase = 1; cin >> T; while (T--) { cin >> W >> H >> L >> M; Max = 0; for (int i = 0; i < M; i++) { scanf("%d", &value[i]); Max += value[i]; } value[M] = 0; for (int i = 0; i < H; i++) scanf("%s", Map[i]); MST(path, INF); // 把距離初始為最大 for (int i = 0; i < H; i++) for (int j = 0; j < W; j++) { if (Map[i][j] == '@') bfs(i, j, 0); else if (Map[i][j] == '<')bfs(i, j, M + 1); else if (Map[i][j] >= 'A' && Map[i][j] <= 'J') bfs(i, j, Map[i][j] - 'A' + 1); } MST(visited, 0); visited[0] = 1; ans = -1; dfs(0, 0, 0); printf("Case %d:/n", icase++); if (ans != -1) printf("The best score is %d./n", ans); else printf("Impossible/n"); if (T) printf("/n"); }}新聞熱點
疑難解答
