【POJ】[1985]Cow Marathon
来源:互联网 发布:linux下php言编程ide 编辑:程序博客网 时间:2024/05/22 03:30
Cow Marathon
Time Limit: 2000MS Memory Limit: 30000K
Case Time Limit: 1000MS
Description
After hearing about the epidemic of obesity in the USA, Farmer John wants his cows to get more exercise, so he has committed to create a bovine marathon for his cows to run. The marathon route will include a pair of farms and a path comprised of a sequence of roads between them. Since FJ wants the cows to get as much exercise as possible he wants to find the two farms on his map that are the farthest apart from each other (distance being measured in terms of total length of road on the path between the two farms). Help him determine the distances between this farthest pair of farms.
Input
Lines 1…..: Same input format as “Navigation Nightmare”.
OutputLine 1: An integer giving the distance between the farthest pair of farms.
Sample Input
7 6
1 6 13 E
6 3 9 E
3 5 7 S
4 1 3 N
2 4 20 W
4 7 2 S
Sample Output
52
Hint
The longest marathon runs from farm 2 via roads 4, 1, 6 and 3 to farm 5 and is of length 20+3+13+9+7=52.
给一个树,让寻找树中两点的最大距离
也就是求树的直径
思路:找出任意一点的最远点u,在找出u的最远点v,则n-v的距离即是最大距离。
可以运用DFS||BFS来进行搜索
因为时间类似而DFS比较简洁
所以这里运用DFS
储存树使用了邻接表
#include<stdio.h>#include<string.h>int n,m;int t,res;int head[100200];int headcnt;struct List { int u,v,w; int next;} edge[100200];void dfs(int u,int v,int w) { if(w>res) { res=w; t=u; } for(int i=head[u]; i!=-1; i=edge[i].next) { if(edge[i].v!=v) { dfs(edge[i].v,u,w+edge[i].w); } }}void add(int u,int v,int w) { edge[headcnt].u=u; edge[headcnt].v=v; edge[headcnt].w=w; edge[headcnt].next=head[u]; head[u]=headcnt++;}int main() { while(scanf("%d %d",&n,&m)!=EOF) { headcnt=0; memset(head,-1,sizeof(head)); while(m--) { int u,v,w; scanf("%d %d %d %*c",&u,&v,&w); add(u,v,w); add(v,u,w); } res=0; dfs(1,0,0); dfs(t,0,0); printf("%d\n",res); } return 0;}
题目地址:【POJ】[1985]Cow Marathon
- POJ 1985 COW MARATHON
- POJ 1985 Cow Marathon
- POJ --1985--Cow Marathon
- poj 1985 Cow Marathon
- POJ 1985 Cow Marathon
- POJ 1985 Cow Marathon
- POJ 1985 Cow Marathon
- poj 1985 Cow Marathon
- poj 1985 Cow Marathon
- poj 1985 Cow Marathon
- POJ -- 1985 Cow Marathon
- 【POJ】[1985]Cow Marathon
- POJ 1985 Cow Marathon
- POJ-1985 Cow Marathon
- POJ 1985 Cow Marathon
- 【POJ 1985 Cow Marathon】
- POJ 1985 Cow Marathon 搜索
- A - Cow Marathon POJ-1985
- Ubuntu安装搜狗拼音相关问题
- VC隐藏任务栏,让窗口全屏
- 师兄帮帮我
- Cow Marathon
- iOS pop到指定的页面
- 【POJ】[1985]Cow Marathon
- poj 2388 Who's in the Middle
- 求最长上升/下降子序列【O(nlgn)】
- Python学习笔记(三)-- 数据结构
- 《JAVA并发编程实践》读书笔记(三)
- java位运算
- Android OpenGL ES学习笔记之常用API
- 第一次机房收费系统总结
- Android收起软键盘,隐藏软键盘