poj 2506 Tiling(递推+大数加法）

来源：互联网发布：罗氏诊断待遇知乎编辑：程序博客网时间：2024/04/29 14:49

Description

In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles?
Here is a sample tiling of a 2x17 rectangle.

Input

Input is a sequence of lines, each line containing an integer number 0 <= n <= 250.

Output

For each line of input, output one integer number in a separate line giving the number of possible tilings of a 2xn rectangle.

Sample Input

2812100200

Sample Output

317127318451004001521529343311354702511071292029505993517027974728227441735014801995855195223534251

公式为：f[x]=f[x-1]+2*f[x-2];

至于为什么f[0]为1，我也不知道。。。我是根据公式以及给出的案例反推的f[0].

#include <stdio.h>#include <string.h>char s[260][200];int main(){    int n, i, a, j, x, b;    memset(s,'0',sizeof(s));    s[0][0]='1';    s[1][0]='1';    s[2][0]='3';    for(i=3;i<=250;i++)    {        for(j=0;j<100;j++)        {            a=(2*(s[i-2][j]-'0')+s[i-1][j]-'0'+s[i][j]-'0');            s[i][j]=a%10+'0';            s[i][j+1]=a/10+'0';        }    }    while(scanf("%d",&n)!=EOF)    {        x=0;        for(i=100;i>=0;i--)        {            if(s[n][i]!='0')            {                x=i;                break;            }        }        for(i=x;i>=0;i--)        {            printf("%c",s[n][i]);        }        printf("\n");    }    return 0;}

0 0