ffi roo which whether win algorithm 種類 using elong

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.

思路：這道題用到的是食物鏈的思想，以（x+n）代表敵對關系

#include <cstdio>
#include <iostream>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;

typedef long long ll;
const int inf = 0x3f3f3f3f;
const int maxn = 1e6;
int sign[maxn];
int n, m, t;
void init()
{
    for(int i = 0; i<maxn; i++)
        sign[i] = i;
}
int get(int x)
{
    if(x == sign[x])
        return x;
    return sign[x] = get(sign[x]);
}
void unio(int x, int y)//合並敵對關系
{
    int a = get(x), b = get(y);
    sign[a] = b;
}
int cmp1(int x, int y)//判斷兩個人是不在同一個幫派
{
    if(get(x) == get(y+n) || get(y) == get(x+n))//如果兩者為敵對關系，則返回1
        return 1;
    return 0;
}
int cmp2(int x, int y)//判斷兩人在同一個幫派
{
    if(get(x) == get(y) || get(x+n) == get(y+n))//如果兩個人不是敵對關系
        return 1;
    return 0;
}
int main()
{
    char bang;
    int a, b;
    scanf("%d", &t);
    for(int i = 0; i<t; i++)
    {
        init();
        scanf("%d%d", &n, &m);
        for(int j = 0; j<m; j++)
        {
            scanf("%s%d%d",&bang,&a,&b);
            if(bang == ‘D‘)
            {
                unio(a, b + n);
                unio(a + n,b);
            }
            else if(bang == ‘A‘)
            {
                if(cmp1(a, b))//如果不在同一個幫派
                    printf("In different gangs.\n");
                else if(cmp2(a,b))//如果在同一個幫派
                    printf("In the same gang.\n");
                else//搜索不到
                    printf("Not sure yet.\n");
            }
        }
    }
    return 0;
}

Find them, Catch them（種類並查集）