zoukankan      html  css  js  c++  java
  • POJ 2704(Pascal's Travels裸dp)

    Language:
    Pascal's Travels
    Time Limit: 1000MS   Memory Limit: 65536K
    Total Submissions: 4821   Accepted: 2139

    Description

    An n x n game board is populated with integers, one nonnegative integer per square. The goal is to travel along any legitimate path from the upper left corner to the lower right corner of the board. The integer in any one square dictates how large a step away from that location must be. If the step size would advance travel off the game board, then a step in that particular direction is forbidden. All steps must be either to the right or toward the bottom. Note that a 0 is a dead end which prevents any further progress. 

    Consider the 4 x 4 board shown in Figure 1, where the solid circle identifies the start position and the dashed circle identifies the target. Figure 2 shows the three paths from the start to the target, with the irrelevant numbers in each removed. 

    Input

    The input contains data for one to thirty boards, followed by a final line containing only the integer -1. The data for a board starts with a line containing a single positive integer n, 4 <= n <= 34, which is the number of rows in this board. This is followed by n rows of data. Each row contains n single digits, 0-9, with no spaces between them.

    Output

    The output consists of one line for each board, containing a single integer, which is the number of paths from the upper left corner to the lower right corner. There will be fewer than 2 63 paths for any board. 

    Sample Input

    4
    2331
    1213
    1231
    3110
    4
    3332
    1213
    1232
    2120
    5
    11101
    01111
    11111
    11101
    11101
    -1
    

    Sample Output

    3
    0
    7

    Hint

    Brute force methods examining every path will likely exceed the allotted time limit. 64-bit integer values are available as long values in Java or long long values using the contest's C/C++ compilers.

    Source

    就是dp……

    一开始忘打‘\n’ wa了……

    #include<cstdio>
    #include<cstdlib>
    #include<algorithm>
    #include<cstring>
    using namespace std;
    #define MAXN (34+1)
    int a[MAXN][MAXN],n;
    long long f[MAXN][MAXN];
    int main()
    {
    	while (scanf("%d",&n)&&n+1)
    	{
    		for (int i=1;i<=n;i++)
    		{
    			char s[MAXN];
    			scanf("%s",s+1);
    			for (int j=1;j<=n;j++) a[i][j]=s[j]-'0';			
    		}
    		memset(f,0,sizeof(f));f[1][1]=1;
    		for (int i=1;i<=n;i++)
    			for (int j=1;j<=n;j++)
    				if (a[i][j])
    				{
    					if (i+a[i][j]<=n) f[i+a[i][j]][j]+=f[i][j];
    					if (j+a[i][j]<=n) f[i][j+a[i][j]]+=f[i][j];
    				}
    		printf("%lld\n",f[n][n]);
    	}
    	return 0;
    }



  • 相关阅读:
    嗅探对方机器,获取机器键盘记录
    python识别图片生成字符模式
    栈 详解
    解决 No result defined for action and result input 异常
    解决hibernate保存数据到mysql中出现乱码问题
    懒加载异常 org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role
    解决springjava.lang.IllegalStateException: BeanFactory not initialized or already closed
    Android Fragment 详解
    脏读|不可重复度|幻读的理解以及Spring定义的五种事务隔离级别
    Spring中的context:annotation-config作用
  • 原文地址:https://www.cnblogs.com/javawebsoa/p/2981428.html
Copyright © 2011-2022 走看看