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https://www.nowcoder.com/acm/contest/156/F
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1 #include 2 #include 3 #include 4 #include 5 #include 6 #include 7 #include 8 #include 9 #include 10 #include 11 #include 12 #include 13 #include 14 using namespace std;15 #define ll long long16 #define minv 1e-617 #define inf 1e918 const ll mod=998244353;19 const long maxn=1e5+5;20 21 vector e[maxn];22 bool vis[maxn]={ 0};23 ll result=0,x,y;24 25 void gcd(ll a,ll b)26 {27 if (b==0)28 {29 x=1;30 y=0;31 }32 else33 {34 gcd(b,a%b);35 ll r;36 r=x;37 x=y;38 y=r-a/b*y;39 }40 }41 42 ll ni(ll s)43 {44 gcd(mod,s%mod);45 return (y%mod+mod)%mod;46 }47 48 void dfs(int d,int dep)49 {50 vis[d]=1;51 result=(result+ni(dep))%mod;52 vector ::iterator i;53 for (i=e[d].begin();i!=e[d].end();i++)54 if (!vis[*i])55 dfs(*i,dep+1);56 }57 58 int main()59 {60 int n,i,x,y;61 scanf("%d",&n);62 for (i=1;i
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