必威官网登录-betway必威官网|体育在线

热门关键词: 必威体育,betway必威官网,必威官网登录,必威app下载

用BFS广度优先搜索

作者: 计算机网络  发布:2019-11-12

poj 1915 Knight Moves,pojknight

Knight Moves

Time Limit: 1000MS   Memory Limit: 30000K
Total Submissions: 26061   Accepted: 12287

Description

Background 
Mr Somurolov, fabulous chess-gamer indeed, asserts that no one else but him can move knights from one position to another so fast. Can you beat him? 
The Problem 
Your task is to write a program to calculate the minimum number of moves needed for a knight to reach one point from another, so that you have the chance to be faster than Somurolov. 
For people not familiar with chess, the possible knight moves are shown in Figure 1. 

图片 1

Input

The input begins with the number n of scenarios on a single line by itself. 
Next follow n scenarios. Each scenario consists of three lines containing integer numbers. The first line specifies the length l of a side of the chess board (4 <= l <= 300). The entire board has size l * l. The second and third line contain pair of integers {0, ..., l-1}*{0, ..., l-1} specifying the starting and ending position of the knight on the board. The integers are separated by a single blank. You can assume that the positions are valid positions on the chess board of that scenario.

Output

For each scenario of the input you have to calculate the minimal amount of knight moves which are necessary to move from the starting point to the ending point. If starting point and ending point are equal,distance is zero. The distance must be written on a single line.

Sample Input

3
8
0 0
7 0
100
0 0
30 50
10
1 1
1 1

Sample Output

5
28
0

Source

TUD Programming Contest 二〇〇三, Darmstadt, 德文y   注意:1.数量的下标是从0起始的    2.只顾vis数组每一回要置0  

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<queue>
 5 #include<cstdlib>
 6 using namespace std;
 7 const int MAXN=1001;
 8 int vis[MAXN][MAXN];
 9 int map[MAXN][MAXN];
10 int n;
11 int bgx,bgy;
12 int edx,edy;
13 int xx[9]={-1,-2,-2,-1,+1,+2,+2,+1};
14 int yy[9]={-2,-1,+1,+2,-2,-1,+1,+2};
15 struct node
16 {
17     int x;
18     int y;
19     int step;
20 };
21 void bfs(int bgx,int bgy)
22 {
23     queue<node>q;
24     node cur;
25     cur.x=bgx;cur.y=bgy;cur.step=0;
26     q.push(cur);
27     vis[cur.x][cur.y]=1;
28     while(q.size()!=0)
29     {
30         cur=q.front();
31         q.pop();
32         if(cur.x==edx&&cur.y==edy)
33         {
34             printf("%dn",cur.step); 
35             return ;
36         } 
37         for(int i=0;i<8;i++)
38         {
39             node nxt;
40             nxt.x=cur.x+xx[i];
41             nxt.y=cur.y+yy[i];
42             nxt.step=cur.step+1;
43             if(vis[nxt.x][nxt.y]==0&&nxt.x>=0&&nxt.x<n&&nxt.y>=0&&nxt.y<n)
44                 q.push(nxt),vis[nxt.x][nxt.y]=1;
45         }
46     }
47 }
48 int main()
49 {
50     int T;
51     scanf("%d",&T);
52     for(int i=1;i<=T;i++)
53     {
54         memset(vis,0,sizeof(vis));
55         scanf("%d",&n);
56         scanf("%d%d%d%d",&bgx,&bgy,&edx,&edy);
57         bfs(bgx,bgy);
58     }
59     return 0;
60 }

 

1915 Knight Moves,pojknight Knight Moves Time Limit: 1000MS Memory Limit: 30000K Total Submissions: 26061 Accepted: 12287 Description Background Mr Somurolov, fabulous chess-...

Knight Moves
Time Limit: 1000MS Memory Limit: 30000K
Total Submissions: 25909 Accepted: 12244
Description

5
28
0
Source

For each scenario of the input you have to calculate the minimal amount of knight moves which are necessary to move from the starting point to the ending point. If starting point and ending point are equal,distance is zero. The distance must be written on a single line.
Sample Input

切切实实的大概会有DFS的减枝优化,笔者并未有试,细心风姿罗曼蒂克想,寻常的DFS应该都会晚点吧,用BFS广度优先搜索

Background
Mr Somurolov, fabulous chess-gamer indeed, asserts that no one else but him can move knights from one position to another so fast. Can you beat him?
The Problem
Your task is to write a program to calculate the minimum number of moves needed for a knight to reach one point from another, so that you have the chance to be faster than Somurolov.
For people not familiar with chess, the possible knight moves are shown in Figure 1.

3
8
0 0
7 0
100
0 0
30 50
10
1 1
1 1
Sample Output

本文由betway必威官网发布于计算机网络,转载请注明出处:用BFS广度优先搜索

关键词: