hdu 5326 Work

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=5326
统计子树大小为k的节点数。。

#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<vector>#include<queue>#include<set>using std::set;using std::pair;using std::swap;using std::queue;using std::multiset;#define pb(e) push_back(e)#define sz(c) (int)(c).size()#define mp(a, b) make_pair(a, b)#define all(c) (c).begin(), (c).end()#define iter(c) decltype((c).begin())#define cls(arr, val) memset(arr, val, sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for(int i = 0; i < (int)n; i++)#define tr(c, i) for(iter(c) i = (c).begin(); i != (c).end(); ++i)const int N = 110;const int INF = 0x3f3f3f3f;struct edge { int to, next; }G[N << 1];bool inq[N];int tot, size[N], head[N];void init(int n) {    tot = 0;    rep(i, n + 1) {        head[i] = -1;        inq[i] = size[i] = false;    }}inline void add_edge(int u, int v) {    G[tot].to = v, G[tot].next = head[u], head[u] = tot++;}void dfs(int u) {    size[u] = 1;    for (int i = head[u]; ~i; i = G[i].next) {        edge &e = G[i];        dfs(e.to);        size[u] += size[e.to];    }}int main() {#ifdef LOCAL    freopen("in.txt", "r", stdin);    freopen("out.txt", "w+", stdout);#endif    int n, k, u, v;    while (~scanf("%d %d", &n, &k)) {        init(n);        rep(i, n - 1) {            scanf("%d %d", &u, &v);            add_edge(u, v);            inq[v] = true;        }        for(int i = 1; i <= n; i++) {            if (!inq[i]) {                u = i;                break;            }        }        int sum = 0;        dfs(u);        for (int i = 1; i <= n; i++) {            if (size[i] == k + 1) sum++;        }        printf("%d\n", sum);    }    return 0;}