POJ Six Degrees of Cowvin Bacon

//276K 16MS
#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

const int INF = 0x7fffffff;
const int maxn = 300;
int d[maxn+5][maxn+5];
int n, m;

void floyd(){
for(int k=1; k<=n; k++){
for(int i=1; i<=n; i++){
for(int j=1; j<=n; j++){
if(d[i][k] != INF && d[k][j] != INF)
d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
}
}
}
}

int main(){
while(scanf("%d%d", &n, &m) != EOF){
for(int i=1; i<=n; i++)
for(int j=1; j<=n; j++)
d[i][j] = (i == j ? 0 : INF);
while(m--){
int num, a[maxn+5];
scanf("%d", &num);
for(int i=1; i<=num; i++)
scanf("%d", &a[i]);
for(int i=1; i<=num-1; i++){
for(int j=i+1; j<=num; j++){
d[a[i]][a[j]] = d[a[j]][a[i]] = 1;
}
}
}
floyd();
int res = INF;
for(int i=1; i<=n; i++){
int sum = 0;
for(int j=1; j<=n; j++){
if(j != i) sum += d[i][j];
}
res = min(res, sum);
}
printf("%d\n", res*100/(n-1));
}
return 0;
}