ZOJ-2771

简单DP，关系式出来后代码就很简洁，注意要用long long，刚开始我用的int果断WA，然后换成大数，后来看了看别人的代码long long竟然可以过，就又换成long long了。。几经周折

#include<stdio.h>int main(){int i;unsigned long long dp[62][3];dp[0][0] = 1;dp[0][1] = dp[0][2] = 0;for (i = 1; i <= 61; i++){dp[i][2] = dp[i - 1][0];dp[i][1] = dp[i - 1][0] + dp[i - 1][1];dp[i][0] = dp[i][1] + dp[i - 1][2];}while (scanf("%d", &i) != EOF)printf("%llu\n", dp[i + 1][0]);return 0;}