HDU4707pet

Description

One day, Lin Ji wake up in the morning and found that his pethamster escaped. He searched in the room but didn’t find the hamster. He tried to use some cheese to trap the hamster. He put the cheese trap in his room and waited for three days. Nothing but cockroaches was caught. He got the map of the school and foundthat there is no cyclic path and every location in the school can be reached from his room. The trap’s manual mention that the pet will always come back if it still in somewhere nearer than distance D. Your task is to help Lin Ji to find out how many possible locations the hamster may found given the map of the school. Assume that the hamster is still hiding in somewhere in the school and distance between each adjacent locations is always one distance unit.

Input

The input contains multiple test cases. Thefirst line is a positive integer T (0

Output

For each test case, outputin a single line the number of possible locations in the school the hamster may be found.

Sample Input

1
10 2
0 1
0 2
0 3
1 4
1 5
2 6
3 7
4 8
6 9

Sample Output

2

Hint

题意

题解：

查找节点深度大于2的个数
把每个节点的连接的点都存入vector 然后从0开始bfs记录每个点的深度

AC代码

#include<cstdio>#include<cstring>#include<stack>#include <set>#include <queue>#include <vector>#include<iostream>#include<algorithm>using namespace std;typedef long long LL;const int mod = 1e9+7;int vis[100005];int step[100005];vector <int > v[100005];queue<int> q;void init(){    for (int i = 0;i < 100005; ++i){        v[i].clear();        step[i] = 0;        vis[i] = 0;    }    while (!q.empty()) q.pop();}int main(){    int t;    scanf("%d",&t);    while (t--){        int n,k;        scanf("%d%d",&n,&k);        init();        int x,y;        for (int i = 0;i < n-1; ++i){            scanf("%d%d",&x,&y);            if (x!=y){                v[x].push_back(y);                v[y].push_back(x);            }        }        q.push(0);        vis[0] = 1;        while (!q.empty()){            int tp = q.front();            q.pop();            for (int i = 0;i < v[tp].size(); ++i){                if (!vis[v[tp][i]]){                    q.push(v[tp][i]);                    step[v[tp][i]] = step[tp] + 1;                    vis[v[tp][i]] = 1;                }            }        }        int sum = 0;        for (int i = 0;i < n; ++i){            if (step[i]>k){                sum++;            }        }        printf("%d\n",sum);    }    return 0;}