poj1847 Tram(最短路)
来源:互联网 发布:机加工报价软件 编辑:程序博客网 时间:2024/05/14 11:55
Tram
Time Limit: 1000MS Memory Limit: 30000KTotal Submissions: 10538 Accepted: 3843
Description
Tram network in Zagreb consists of a number of intersections and rails connecting some of them. In every intersection there is a switch pointing to the one of the rails going out of the intersection. When the tram enters the intersection it can leave only in the direction the switch is pointing. If the driver wants to go some other way, he/she has to manually change the switch.
When a driver has do drive from intersection A to the intersection B he/she tries to choose the route that will minimize the number of times he/she will have to change the switches manually.
Write a program that will calculate the minimal number of switch changes necessary to travel from intersection A to intersection B.
When a driver has do drive from intersection A to the intersection B he/she tries to choose the route that will minimize the number of times he/she will have to change the switches manually.
Write a program that will calculate the minimal number of switch changes necessary to travel from intersection A to intersection B.
Input
The first line of the input contains integers N, A and B, separated by a single blank character, 2 <= N <= 100, 1 <= A, B <= N, N is the number of intersections in the network, and intersections are numbered from 1 to N.
Each of the following N lines contain a sequence of integers separated by a single blank character. First number in the i-th line, Ki (0 <= Ki <= N-1), represents the number of rails going out of the i-th intersection. Next Ki numbers represents the intersections directly connected to the i-th intersection.Switch in the i-th intersection is initially pointing in the direction of the first intersection listed.
Each of the following N lines contain a sequence of integers separated by a single blank character. First number in the i-th line, Ki (0 <= Ki <= N-1), represents the number of rails going out of the i-th intersection. Next Ki numbers represents the intersections directly connected to the i-th intersection.Switch in the i-th intersection is initially pointing in the direction of the first intersection listed.
Output
The first and only line of the output should contain the target minimal number. If there is no route from A to B the line should contain the integer "-1".
Sample Input
3 2 12 2 32 3 12 1 2
Sample Output
0
Source
Croatia OI 2002 Regional - Juniors
/*读不懂题真无语。。。。,题意是初始指向第一个点,在第一个点的时候就不用转,其他需要转动,没有输入就不能联通Time:2015-1-7 12:40*/#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int INF=0x3f3f3f3f;const int MAX=160;int g[MAX][MAX];int main(){ int n,s,t,k; int u,v; while(scanf("%d%d%d",&n,&s,&t)!=EOF){ for(int i=1;i<=n;i++){ for(int j=i;j<=n;j++){ if(i==j)g[i][j]=0; else g[j][i]=g[i][j]=INF; } } for(int i=1;i<=n;i++){ scanf("%d",&k); int cnt=0; while(k--){ scanf("%d",&v); if(!cnt) g[i][v]=0; else g[i][v]=1; cnt++; } } for(int k=1;k<=n;k++){ for(int i=1;i<=n;i++){ for(int j=1;j<=n;j++){ g[i][j]=min(g[i][j],g[i][k]+g[k][j]); } } } if(g[s][t]!=INF) printf("%d\n",g[s][t]); else printf("-1\n"); }return 0;}
0 0
- poj1847 Tram(最短路)
- POJ1847--Tram 【最短路spfa】
- POJ1847 Tram ACM解题报告(dijkstra求最短路)
- POJ1847 Tram(最短路径)
- POJ1847 Tram最短路径 Dijkstra
- POJ1847:Tram
- POJ1847---Tram
- [poj1847] Tram
- poj1847 Tram
- poj1847~简单最短路问题
- HDU1847 Tram(最短路)
- Tram [最短路][spfa]
- poj1847 - Tram (最短路径问题) (Dijkstra)
- Tram(poj1847,floyd)
- poj1847 Tram SPFA
- POJ 1847 Tram 最短路
- POJ 1847 Tram(最短路)
- POJ - 1847Tram最短路
- http报 206 Partial Content
- rtsp协议详解
- 海尔集团谭丽霞:互联网时代应颠覆传统思维
- 盒子阴影
- js数据类型以及"==","==="运算符、if()语句
- poj1847 Tram(最短路)
- 背景
- 6666666666666
- jQuery性能优化
- 文本
- 集合研究------Map
- 日经春秋 20150107
- Unique Paths II
- 由C#快速入门Java