【并查集】 HDOJ 3461 Code Lock

这个并查集比较难想，

#include <iostream>
#include <queue> 
#include <stack> 
#include <map> 
#include <set> 
#include <bitset> 
#include <cstdio> 
#include <algorithm> 
#include <cstring> 
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 10000005
#define maxm 10005
#define eps 1e-7
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid 
#define rson o<<1 | 1, mid+1, R
#define pii pair<int, int>
#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
// head

int f[maxn];
int n, m, cnt;

int find(int x)
{
	return f[x] == x ? f[x] : find(f[x]);
}

void merge(int a, int b)
{
	int aa = find(a), bb = find(b);
	if(aa != bb) {
		f[aa] = bb;
		cnt++;
	}
}

void read()
{
	int l, r;
	for(int i = 0; i <= n; i++) f[i] = i;
	cnt = 0;
	while(m--) {
		scanf("%d%d", &l, &r);
		merge(--l, r);
	}
}

void work()
{
	printf("%lld\n", powmod(26, n - cnt));
}

int main()
{
	while(scanf("%d%d", &n, &m)!=EOF) {
		read();
		work();
	}
	
	
	
	return 0;
}