错误但AC
正确
我的dp写成 dp[i][j][1] = max(dp[i][j-1][0], dp[i-1][j-1][1] + a[i]); 竟然能过
dp[i][j][1] = max(dp[i][j-1][0], dp[i-1][j-1][1] + a[i]);
