pat1126 Eulerian Path

题意：给一个无向图，判断这个图是欧拉图还是半欧拉图还是不是欧拉图。

思路：并查集判断是否只有一个联通分量，记录每个点的度数。

代码

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>

using namespace std;

const int MAX_N = 510;
int N, M;
int x, y;
int dig[MAX_N];
int par[MAX_N], parc = 0;

void init(int n) {for (int i = 1; i <= n; i++) par[i] = i;}
int find(int x) {
    if (x == par[x]) return x;
    return par[x] = find(par[x]);
}
void uni(int x, int y) {
    x = find(x); y = find(y);
    if (x == y) return ;
    par[x] = y;
}

int main() {
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    memset(dig, 0, sizeof(dig));
    scanf("%d %d", &N, &M); init(N);
    while (M--) scanf("%d %d", &x, &y), dig[x]++, dig[y]++, uni(x, y);
    parc = 0;
    for (int i = 1; i <= N; i++) if (i == find(i)) parc++;
    int cnt = 0;
    for (int i = 1; i <= N; i++) {
        if (i > 1) printf(" ");
        printf("%d", dig[i]);
        if (dig[i] & 1) cnt++;
    } 
    printf("\n");
    if (cnt == 0 && parc == 1) printf("Eulerian\n");
    else if (cnt == 2 && parc == 1) printf("Semi-Eulerian\n");
    else printf("Non-Eulerian\n");
    return 0;
}