Euler tour

#include <bits/stdc++.h>

using namespace std;

#define MAX 7
vector<int> adj[MAX][MAX];
int deg[MAX];
bool vis[MAX];

bool dfs(int u, int v)
{
    if(u == v) return true;
    vis[u] = true;
    for(int i=0; i<MAX; i++){
        if(adj[u][i].size() > 0 || adj[i][u].size() > 0 && vis[i] == false){
            if(dfs(i, v)) return true;
        }
    }
    return false;
}

bool is_connected()
{
    memset(vis, false, sizeof vis);
    for(int i=0; i<MAX; i++){
        if(deg[i] > 0){
            dfs(i, -1);
            break;
        }
    }
    for(int i=0; i<MAX; i++){
        if(deg[i] > 0 && vis[i] == false) return false;
    }
    return true;
}

int main()
{
    int n;
    scanf("%d", &n);
    memset(deg, 0, sizeof deg);
    for(int i=0; i<n; i++){
        int u, v;
        scanf("%d %d", &u, &v);
        deg[u]++;
        deg[v]++;
        adj[u][v].push_back(i+1);
    }
    int odd = 0, curNode = -1;
    for(int i=0; i<MAX; i++){
        if(deg[i]%2 == 1){
            odd++;
            curNode = i;
        }
    }
    if((odd != 0 && odd != 2) || is_connected()){
        printf("-1");
        return 0;
    }
    if(odd == 0){
        for(int i=0; i<MAX; i++){
            if(deg[i] != 0){
                curNode = i;
                break;
            }
        }
    }
    for(int i=0; i<n; i++){
        bool forwrd;
        for(int j=0; j<MAX; j++){
            int selected_ind;
            if(adj[curNode][j].size() > 0 || adj[j][curNode].size() > 0){
                if(adj[curNode][j].size() > 0){
                    selected_ind = adj[curNode][j].back();
                    adj[curNode][j].pop_back();
                    forwrd = true;
                }
                else {
                    selected_ind = adj[j][curNode].back();
                    adj[j][curNode].pop_back();
                    forwrd = false;
                }
                deg[curNode]--;
                deg[j]--;
                memset(vis, 0, sizeof vis);
                if(deg[curNode] == 0 || dfs(curNode, j) == true){
                    curNode = j;
                    printf("%d %c\n", selected_ind, forwrd ? '+' : '-');
                    break;
                }
                else {
                    deg[curNode]++;
                    deg[j]++;
                    if(forwrd) adj[curNode][j].push_back(selected_ind);
                    else adj[j][curNode].push_back(selected_ind);
                }
            }
        }
    }
}