Num 36 : ZOJ 2100 [ 深度优先搜索算法 ] [ 回溯 ]
来源:互联网 发布:数据采集标准规范 编辑:程序博客网 时间:2024/05/16 12:50
该题是用回溯法来解决的题:
题目:
It is spring time and farmers have to plant seeds in the field. Tom has a nice field,which is a rectangle with n * m squares. There are big stones in some of the squares.
Tom has a seeding-machine. At the beginning, the machine lies in the top left corner of the field. After the machine finishes one square, Tom drives it into an adjacent square, and continues seeding. In order to protect the machine, Tom will not drive it into a square that contains stones. It is not allowed to drive the machine into a square that been seeded before, either.
Tom wants to seed all the squares that do not contain stones. Is it possible?
Input
The first line of each test case contains two integers n and m that denote the size of the field. (1 < n, m < 7) The next n lines give the field, each of which contains m characters. 'S' is a square with stones, and '.' is a square without stones.
Input is terminated with two 0's. This case is not to be processed.
Output
For each test case, print "YES" if Tom can make it, or "NO" otherwise.
Sample Input
4 4
.S..
.S..
....
....
4 4
....
...S
....
...S
0 0
Sample Output
YES
NO
题目大意:
从左上角开始行进,能不能不走回头路的把地图上所有点走一遍;( S代表障碍物 );
题目分析:
从左上角开始,利用回溯法进行深搜,判断有没有一种情况,能不回头的把一条路走完;
AC代码:
#include<stdio.h>#include<stdlib.h>#include<string.h>int x,y,m,n,snum,max=0,flag;char map[10][10];void fun(int x,int y){if(x<1||x>m||y<1||y>n) return; if(map[x][y]=='S') return; if(flag==1) return;map[x][y]='S';snum++;if(snum==m*n) { flag=1; return; }fun(x-1,y);fun(x+1,y);fun(x,y-1);fun(x,y+1);snum--;map[x][y]='.';}int main(){int i,j;while(scanf("%d%d",&m,&n),m|n){snum=0;for(i=1;i<=m;i++)for(j=1;j<=n;j++){scanf(" %c",&map[i][j]);if(map[i][j]=='S') snum++;}flag=0;fun(1,1);if(flag) printf("YES\n");else printf("NO\n");}return 0;}
- Num 36 : ZOJ 2100 [ 深度优先搜索算法 ] [ 回溯 ]
- Num 35 : HDOJ : 1241 Oil Deposits [ 深度优先搜索算法 ] [ 非回溯 ][ 图论 ]
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- [算法专题] 深度优先搜索&回溯剪枝
- BFS广度优先搜索 DFS深度优先搜索 回溯算法
- hud1010回溯深度优先搜索
- 回溯法--深度优先搜索
- 栈:深度优先搜索与回溯算法求解迷宫
- 搜索算法简单介绍:回溯法,深度优先搜索,广度优先搜索
- ZOJ 1002 Fire Net 深度优先搜索算法
- Eclipse下open iExplorer插件安装
- 软件工程
- Thrift 基本使用
- 最近刚学到容器Vector,就顺便编写了两个简单的小程序
- linux下网络编程3:UDP广播传输文件
- Num 36 : ZOJ 2100 [ 深度优先搜索算法 ] [ 回溯 ]
- 浏览器缓存详解:expires,cache-control,last-modified,etag详细说明
- C++学习小结
- 【开源专访】JFinal作者詹波:以极简方式实现Web项目的极速开发
- QDataStream的一个价值1万元的痛
- 项目管理心得:一个项目经理的个人体会、经验总结
- Eclipse集成tomcat
- 字典树
- listview控件焦点冲突解决办法