思路:并查集一套带走. AC代码 #include <stdio.h> #include <string.h> #include <algorithm> using namespace std; const int maxn = 10000+5; int par[maxn], vis[maxn]; int findRoot(int x) { return x == par[x] ? x : par[x] = findRoot(par[x]); } void unionS…

1118. Birds in Forest (25) 时间限制 150 ms 内存限制 65536 kB 代码长度限制 16000 B 判题程序 Standard 作者 CHEN, Yue Some scientists took pictures of thousands of birds in a forest. Assume that all the birds appear in the same picture belong to the same tree. You are supp…

题意:给定每一点离他最远的点,问是这个森林里有多少棵树. 析:并查集,最后统计不同根结点的数目即可. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #include <cmath> #include <iostream> #include &…

Some scientists took pictures of thousands of birds in a forest. Assume that all the birds appear in the same picture belong to the same tree. You are supposed to help the scientists to count the maximum number of trees in the forest, and for any pai…

此文章 同步发布在CSDN:https://blog.csdn.net/weixin_44385565/article/details/89819984   1118 Birds in Forest (25 分)   Some scientists took pictures of thousands of birds in a forest. Assume that all the birds appear in the same picture belong to the same tree…

并查集合并 #include<iostream> using namespace std; const int MAX = 10010; int father[MAX],root[MAX]; int findfather(int x){ if(x==father[x]) return x; else{ int F=findfather(father[x]); father[x]=F; return F; } } void Union(int a , int b){ int faA=findfa…

如题... #include <iostream> #include <cstdio> #include <algorithm> #include <string.h> using namespace std; /* 并查集水题 */ +; struct UF{ int father[maxn]; void init(){ ;i<maxn;i++) father[i]=i; } int find_root(int x){ if(father[x]!=x…

1118. Birds in Forest (25) Some scientists took pictures of thousands of birds in a forest. Assume that all the birds appear in the same picture belong to the same tree. You are supposed to help the scientists to count the maximum number of trees in…

http://codeforces.com/problemset/problem/755/C 题意:该图是类似于树,给出n个点,接下来p[i]表示在树上离 i 距离最远的 id 是p[i],如果距离相等则p[i]是 id 较小的点. 思路:一开始没什么想法,画几分钟图发现不到什么东西,后来想着 i 和 p[i] 有关系,那么就代表 i 和 p[i] 是属于同一棵树,那么不就是并查集了嘛.抱着试一试的心态搞了一下居然过了. #include <cstdio> #include <cstri…

题意:给定n个数,Ai的下标为1~n.对于每一个i,Ai与i在同一个树上,且是与i最远的点中id最小的点(这个条件变相的说明i与Ai连通).求森林中树的个数. 分析:若i与Ai连通,则在同一个树上,因此连通块的个数就是树的个数.并查集即可. #pragma comment(linker, "/STACK:102400000, 102400000") #include<cstdio> #include<cstring> #include<cstdlib>…