nyoj1138 The number of maximum subset 递推

题目链接~传送门

题目大意：no two elements in the subset should be adjacent

                   it shouldn't be possible to add numbers to the subset without violating the first condition

                  求最大的子集的个数

解题思路：123456111 31 31 3 51 3 5 2222 42 42 4 6   1 42 51 3 6    1 42 5     1 4 6      

有对比可看出，f(n)是由f(n-2)和f(n-3) 递推过来的

所以可得代码

 #include<stdio.h>int main(){    int n;    int a[100];    a[1]=1;a[2]=2;a[3]=2;    for(int i=4;i<77;i++)        a[i]=a[i-3]+a[i-2];    while(scanf("%d",&n)!=EOF) printf("%d\n",a[n]);}