uva 10054 The Necklace

#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<string.h>
using namespace std;
int map[60][60];
int vis[60];
int num[60];
int counts,n,b;
void dfs(int d)
{
    vis[d]=1;
    counts++;
    for(int i=0;i<=b;i++)
    {
        if(map[d][i]&&!vis[i])
        {
            dfs(i);
        }
    }
    return ;
}
void euler(int a)
{
    for(int i=1;i<=b;i++)
    {
        if(map[a][i])
        {
            map[a][i]--;
            map[i][a]--;
            euler(i);
            printf("%d %d
",i,a);
        }
    }
    return;
}
int main()
{
    int ncase,x,y,colorcont;
    scanf("%d",&ncase);
    for(int k=0;k<ncase;k++)
    {
        if(k)
            printf("
");
        memset(vis,0,sizeof(vis));
        memset(map,0,sizeof(map));
        memset(num,0,sizeof(num));
        scanf("%d",&n);
        for(int i=0;i<n;i++)
        {
            scanf("%d%d",&x,&y);
            map[x][y]++;
            map[y][x]++;
            num[x]++;
            num[y]++;
        }
        counts=0;
        colorcont=0;
        int flag=0;
        for(int i=1;i<56;i++)
        {
            if(num[i]) {colorcont++;b=i;}
            if(num[i]%2!=0) {flag=1;break;}
        }
        printf("Case #%d
",k+1);
        if(!flag)
        {
            dfs(b);
            if(counts!=colorcont)
                printf("some beads may be lost
");
            else
                euler(b);
        }
        else
            printf("some beads may be lost
");
    }
}