HDU 2563 统计问题 (DFS + 打表)

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long LL;const int MAXN = 20 + 5;LL M[MAXN << 2][MAXN << 2],dp[MAXN];bool vis[MAXN << 2][MAXN << 2];int C, n;void dfs(int pos,int x,int y){if(pos > 16) return;if(vis[x][y]) return;dp[pos] ++;vis[x][y] = true;dfs(pos + 1,x + 1, y);dfs(pos + 1,x, y + 1);dfs(pos + 1,x, y – 1);vis[x][y] = false;}void init(){memset(dp, 0, sizeof(dp));memset(vis,false,sizeof(vis));dp[20]=54608393;dp[19]=22619537;dp[18]=9369319;dp[17]=3880899;dfs(0,0,50);}int main(){init();scanf("%d", &C);while(C –){scanf("%d", &n);printf("%I64d\n",dp[n]);}return 0;}

，也有善意的提醒：何不去远方！昆明呀——赶一个花海;