HDU1143（3*N的地板铺1*2的砖）

Tri Tiling

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 3004    Accepted Submission(s): 1687

Problem Description

In how many ways can you tile a 3xn rectangle with 2x1 dominoes? Here is a sample tiling of a 3x12 rectangle.

 

Input

Input consists of several test cases followed by a line containing -1. Each test case is a line containing an integer 0 ≤ n ≤ 30. 

 

Output

For each test case, output one integer number giving the number of possible tilings. 

 

Sample Input

2

8

12

-1

 

Sample Output

3

153

2131

 

Source

University of Waterloo Local Contest 2005.09.24

 

思路详见：动态规划

我的代码：

const int maxn = ;

int dp[maxn][];

void init() {
    dp[][] = dp[][] = ;
    dp[][] = ;
    dp[][] = dp[][] = ;
    dp[][] = ;
    for (int i = ; i <= ; i ++) {
        dp[i][] = dp[i-][] + dp[i-][] + dp[i-][];
        dp[i][] = dp[i-][];
        dp[i][] = dp[i-][] + dp[i][];
    }
}

int main() {
    int n;
    init();
    while (~scanf("%d", &n)) {
        if (n == -) break;
        printf("%d\n", dp[n][]);
    }
    return ;
}

Discuss里的代码：

const int MAX=;
int s[MAX];
int main()
{
    int i,n;
    s[]=;
    s[]=;
    for(i=;i<MAX;i+=)
    {
        s[i]=*s[i-]-s[i-];
    }
    while(cin>>n,n>=)
    {
        if(n&)
            cout<<<<endl;
        else
            cout<<s[n]<<endl;
    }
    return ;
}