题意：一棵N个结点(编号从0开始)的树，根结点为0，求到根结点的距离大于D的结点个数（0 < 测试组数T <= 10, 0<N<=100000, 0<D<N）。

题目链接：

——>>统计吧。。。

 

#include 
    
     #include 
     
      using namespace std;const int maxn = 100000 + 10;int D, head[maxn], nxt[maxn<<1], v[maxn<<1], ecnt, d[maxn], ret;void init(){    memset(head, -1, sizeof(head));    ecnt = 0;    ret = 0;}void addEdge(int uu, int vv){    v[ecnt] = vv;    nxt[ecnt] = head[uu];    head[uu] = ecnt;    ecnt++;}void dfs(int x, int fa){    if(d[x] > D) ret++;    for(int e = head[x]; e != -1; e = nxt[e]) if(v[e] != fa){        d[v[e]] = d[x] + 1;        dfs(v[e], x);    }}void solve(){    d[0] = 0;    dfs(0, -1);    printf("%d\n", ret);}int main(){    int T, N, uu, vv;    scanf("%d", &T);    while(T--){        init();        scanf("%d%d", &N, &D);        for(int i = 0; i < N-1; i++){            scanf("%d%d", &uu, &vv);            addEdge(uu, vv);            addEdge(vv, uu);        }        solve();    }    return 0;}