hdu 4786 Fibonacci Tree(并查集)

题目链接：hdu 4786 Fibonacci Tree

解题思路

首先判断是否可以连通，然后对黑白边分别做并查集连通求连通分量，连通分量即为对应白黑边必须选的边数。

代码

#include <cstdio>#include <cstring>#include <vector>#include <algorithm>using namespace std;const int maxn = 1e5 + 5;//typedef pair<int,int> pii;int N, M, C[3], F[3][maxn];int find (int u, int* f) { return f[u] == u ? u : f[u] = find(f[u], f); }void link(int u, int v, int k) {    int fu = find(u, F[k]);    int fv = find(v, F[k]);    if (fu != fv) {        C[k]--;        F[k][fu] = fv;    }}void init () {    scanf("%d%d", &N, &M);    for (int i = 1; i <= N; i++) {        for (int j = 0; j < 3; j++) F[j][i] = i;    }    C[0] = C[1] = C[2] = N;    int u, v, k;    for (int i = 0; i < M; i++) {        scanf("%d%d%d", &u, &v, &k);        link(u, v, k);        link(u, v, 2);    }}bool judge () {    if (C[2] != 1) return false;    int l = C[0]-1, r = N-C[1];    int p = 1, q = 1;    while (q < N) {        if (l <= q && q <= r) return true;        int tmp = p + q;        p = q;        q = tmp;    }    return false;}int main () {    int cas;    scanf("%d", &cas);    for (int kcas = 1; kcas <= cas; kcas++) {        init();        printf("Case #%d: %s\n", kcas, judge () ? "Yes" : "No");    }    return 0;}