Description

The police office in Tadu City decides to say ends to the chaos, as launch actions to root up the TWO gangs in the city, Gang Dragon and Gang Snake. However, the police first needs to identify which gang a criminal belongs to. The present question is, given two criminals; do they belong to a same clan? You must give your judgment based on incomplete information. (Since the gangsters are always acting secretly.)

Assume N (N <= 10^5) criminals are currently in Tadu City, numbered from 1 to N. And of course, at least one of them belongs to Gang Dragon, and the same for Gang Snake. You will be given M (M <= 10^5) messages in sequence, which are in the following two kinds:

  1. D [a] [b]
    where [a] and [b] are the numbers of two criminals, and they belong to different gangs.

  2. A [a] [b]
    where [a] and [b] are the numbers of two criminals. This requires you to decide whether a and b belong to a same gang.
    Input

The first line of the input contains a single integer T (1 <= T <= 20), the number of test cases. Then T cases follow. Each test case begins with a line with two integers N and M, followed by M lines each containing one message as described above.
Output

For each message “A [a] [b]” in each case, your program should give the judgment based on the information got before. The answers might be one of “In the same gang.”, “In different gangs.” and “Not sure yet.”
Sample Input

1
5 5
A 1 2
D 1 2
A 1 2
D 2 4
A 1 4
Sample Output

Not sure yet.
In different gangs.
In the same gang.
Source

开始复习并查集。
复习第一题：
思路，记一下每个节点与他父亲是否属于同一个gang，没了。
注意一下更新的细节。
具体看代码吧。

顺便说一下，POJ上不能用#include 

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define N 100010
using namespace std;
int n, m, f[N], g[N];
int Find(int x)
{
    if(f[x] == x) return f[x];
    int temp = f[x];
    f[x] = Find(temp);
    if(g[temp] != 0) g[x] = 1 - g[x]; 
    return f[x];
}

inline int read()
{
    int x = 0, f = 1; char ch = getchar();
    while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); }
    while (ch >= '0' && ch <= '9') { x = x * 10 + ch - '0'; ch = getchar(); }
    return x * f;
}

void Work()
{
    n = read();
    for(int i = 1; i <= n; i ++)
        f[i] = i, g[i] = 0;
    int m = read();

    while(m --)
    {
        char ch;
        scanf("%c", &ch);
        if(ch == 'A')
        {
            int a = read(), b = read();
            int x = Find(a), y = Find(b);
            if(x != y) printf("Not sure yet.\n");
            else 
            {
                if(g[a] == g[b]) printf("In the same gang.\n");
                else printf("In different gangs.\n");
            }
        }
        else 
        {
            int a = read(), b = read();
            int x = Find(a), y = Find(b);
            f[y] = x;
            if(g[a] == g[b]) g[y] = 1;
            else g[y] = 0;
        }
    }
}

int main()
{
    int T = read();
    while(T --)
    {
        Work();
    }
    return 0;
}