并查集 hdu 1856 示例

来源：互联网发布：2015广告主投放数据编辑：程序博客网时间：2024/05/22 03:37

#include <iostream>#include <string>#include <cstring>#include <cstdlib>#include <cstdio>#include <cmath>#include <vector>#include <stack>#include <deque>#include <queue>#include <bitset>#include <list>#include <map>#include <set>#include <iterator>#include <algorithm>#include <functional>#include <utility>#include <sstream>#include <climits>#include <cassert>#define BUG puts("here!!!");using namespace std;const int N = 100005;struct Node {    int par;    int sum;};int SUM;Node p[2*N + 5];void makeSet(int n) {    for(int i = 0; i <= 2*n; i++) {        p[i].par = i;        p[i].sum = 1;    }    SUM = 1;}int find(int a) {    if(a == p[a].par) return a;    return p[a].par = find(p[a].par);}void union1(int a, int b) {    int fa = find(a);    int fb = find(b);    if(fa != fb) {        p[fa].par = fb;        p[fb].sum += p[fa].sum;    }    if(p[fb].sum > SUM) {        SUM = p[fb].sum;    }}int main() {    int n, a, b;    while(scanf("%d", &n) == 1) {        makeSet(n);        while(n--) {            scanf("%d%d", &a, &b);            union1(a, b);        }        printf("%d\n", SUM);    }    return 0;}

Sample Input
4
1 2
3 4
5 6
1 6
4
1 2
3 4
5 6
7 8
Sample Output
4
2