1063. Set Similarity

#include <iostream>
#include <cstdio>
#include <string>
#include <vector>
#include <algorithm>
#include <set>
#include <memory.h>
using namespace std;

double res[60][60];
vector<set<int> >v;

double cal(int x, int y)
{
	if(!(res[x][y] < 0)) return res[x][y];
	set<int>::iterator it1 = v[x].begin();
	set<int>::iterator it2 = v[y].begin();
	int nc = 0;
	while(it1 != v[x].end() && it2 != v[y].end())
	{
		if(*it1 == *it2) 
		{
			nc ++ ;
			it1 ++;
			it2 ++;
		}
		else if(*it1 < *it2)
		{
			it1 ++;
		}
		else it2 ++;
	}
	int nt = v[x].size() + v[y].size() - nc;
	res[x][y] = 100.0 * nc / nt;
	return res[x][y];
}

void init_res()
{
	for(int i = 0; i < 60; i ++)
		for(int j = 0; j < 60; j ++) res[i][j] = -1;
}

int main()
{
	init_res();
	
	int n, m, x;
	scanf("%d", &n);
	for(int i = 0; i < n; i ++)
	{
		scanf("%d", &m);
		set<int>s;
		for(int j = 0; j < m; j ++)
		{
			scanf("%d", &x);
			s.insert(x);
		}
		v.push_back(s);
	}
	char c = '%';
	int k, y;
	scanf("%d", &k);
	while(k--)
	{
		scanf("%d %d", &x, &y);
		printf("%.1f%c\n", cal(x-1, y-1), c);
	}
	
	return 0;
}