Submission #1651278

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Source Code Expand

#include<bits/stdc++.h>
#define ll long long
#define mod 1000000007
#define N 109
using namespace std;

int n,m,K,tot=1,fst[N],pnt[N<<1],nxt[N<<1],dad[N],d[N],eg[N];
int cbn[N<<1][N<<1],fa[N],sum[N],sz[N]; bool vis[N],bo[N];
int gcd(int x,int y){ return y?gcd(y,x%y):x; }
int ksm(int x,int y){
	int z=1; for (; y; y>>=1,x=(ll)x*x%mod) if (y&1) z=(ll)z*x%mod;
	return z;
}
void add(int x,int y){
	pnt[++tot]=y; nxt[tot]=fst[x]; fst[x]=tot;
}
int getfa(int x){ return x==fa[x]?x:fa[x]=getfa(fa[x]); }
void mrg(int x,int y){
	x=getfa(x); y=getfa(y);
	sz[y]+=sz[x]; sum[y]+=sum[x]; fa[x]=y;
}
void dfs(int x,int p){
	int i,y; vis[x]=1;
	for (i=fst[x]; i; i=nxt[i]) if (i^p^1){
		y=pnt[i];
		if (!vis[y]){
			dad[y]=x; d[y]=d[x]+1;
			eg[y]=i>>1; bo[i>>1]=1; sz[i>>1]=0;
			dfs(y,i);
		}
	}
}
int main(){
	scanf("%d%d%d",&n,&m,&K);
	int i,j,x,y;
	for (i=0; i<=n+K; i++)
		for (j=cbn[i][0]=1; j<=i; j++)
			cbn[i][j]=(cbn[i-1][j]+cbn[i-1][j-1])%mod;
	for (i=1; i<=m; i++){
		scanf("%d%d",&x,&y);
		add(x,y); add(y,x);
	}
	for (i=1; i<=m; i++){
		fa[i]=i; sz[i]=sum[i]=1;
	}
	for (i=1; i<=n; i++) if (!vis[i]) dfs(i,0);
	for (i=1; i<=m; i++) if (!bo[i]){
		x=pnt[i<<1]; y=pnt[i<<1|1];
		if (d[x]<d[y]) swap(x,y);
		for (; x!=y; x=dad[x]) mrg(eg[x],i);
	}
	int ans=1;
	for (i=1; i<=m; i++) if (getfa(i)==i){
		if (sz[i]>1)
			ans=(ll)ans*cbn[sum[i]+K-1][K-1]%mod;
		else{
			for (j=1,x=0; j<=sum[i]; j++)
				x=(x+ksm(K,gcd(j,sum[i])))%mod;
			ans=(ll)ans*x%mod*ksm(sum[i],mod-2)%mod;
		}
	}
	printf("%d\n",ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:34:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d",&n,&m,&K);
                          ^
./Main.cpp:40:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&x,&y);
                      ^

Judge Result