POJ 1125 Stockbroker Grapevine

Time Limit:1000MS    Memory Limit:10000KB     64bit IO Format:%lld & %llu

SubmitStatus

Description

Input

Output

Sample Input

Sample Output

Hint

Description

Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Bessie needs her beauty sleep, so she wants to get back as quickly as possible.

Farmer John's field has N (2 <= N <= 1000) landmarks in it, uniquely numbered 1..N. Landmark 1 is the barn; the apple tree grove in which Bessie stands all day is landmark N. Cows travel in the field using T (1 <= T <= 2000) bidirectional cow-trails of various lengths between the landmarks. Bessie is not confident of her navigation ability, so she always stays on a trail from its start to its end once she starts it.

Given the trails between the landmarks, determine the minimum distance Bessie must walk to get back to the barn. It is guaranteed that some such route exists.

Input

* Line 1: Two integers: T and N

* Lines 2..T+1: Each line describes a trail as three space-separated integers. The first two integers are the landmarks between which the trail travels. The third integer is the length of the trail, range 1..100.

Output

* Line 1: A single integer, the minimum distance that Bessie must travel to get from landmark N to landmark 1.

Sample Input

5 51 2 202 3 303 4 204 5 201 5 100

Sample Output

90

Hint

INPUT DETAILS:

There are five landmarks.

OUTPUT DETAILS:

Bessie can get home by following trails 4, 3, 2, and 1.

Description

Stockbrokers are known to overreact to rumours. You have been contracted to develop a method of spreading disinformation amongst the stockbrokers to give your employer the tactical edge in the stock market. For maximum effect, you have to spread the rumours in the fastest possible way.

Unfortunately for you, stockbrokers only trust information coming from their "Trusted sources" This means you have to take into account the structure of their contacts when starting a rumour. It takes a certain amount of time for a specific stockbroker to pass the rumour on to each of his colleagues. Your task will be to write a program that tells you which stockbroker to choose as your starting point for the rumour, as well as the time it will take for the rumour to spread throughout the stockbroker community. This duration is measured as the time needed for the last person to receive the information.

Input

Your program will input data for different sets of stockbrokers. Each set starts with a line with the number of stockbrokers. Following this is a line for each stockbroker which contains the number of people who they have contact with, who these people are, and the time taken for them to pass the message to each person. The format of each stockbroker line is as follows: The line starts with the number of contacts (n), followed by n pairs of integers, one pair for each contact. Each pair lists first a number referring to the contact (e.g. a '1' means person number one in the set), followed by the time in minutes taken to pass a message to that person. There are no special punctuation symbols or spacing rules.

Each person is numbered 1 through to the number of stockbrokers. The time taken to pass the message on will be between 1 and 10 minutes (inclusive), and the number of contacts will range between 0 and one less than the number of stockbrokers. The number of stockbrokers will range from 1 to 100. The input is terminated by a set of stockbrokers containing 0 (zero) people.

Output

For each set of data, your program must output a single line containing the person who results in the fastest message transmission, and how long before the last person will receive any given message after you give it to this person, measured in integer minutes.
It is possible that your program will receive a network of connections that excludes some persons, i.e. some people may be unreachable. If your program detects such a broken network, simply output the message "disjoint". Note that the time taken to pass the message from person A to person B is not necessarily the same as the time taken to pass it from B to A, if such transmission is possible at all.

Sample Input

32 2 4 3 52 1 2 3 62 1 2 2 253 4 4 2 8 5 31 5 84 1 6 4 10 2 7 5 202 2 5 1 50

Sample Output

3 23 10

题意：第一排输入经纪人的个数，接下来"第i排"第一个数表示有几对关系好的经济人，只有关系好的才能互相传递消息，一对数据j,t表示第i个经济人与第j个经济人关系好，他们之间传递消息需要t这个时间，求从哪个经纪人开始，需要的时间最短

AC代码：

#include<cstdio>#include<cstdlib>#include<cstring>#include<iostream>#include<algorithm>#define Inf 0x3fffffffusing namespace std;int mp[101][101];int main(){    int n,j,t,m,maxx,minn;    while(scanf("%d",&n) && n)    {        for(int i=1; i<=n; i++)        {            mp[i][i]=0;            for(int j=1; j<i; j++)                mp[i][j]=mp[j][i]=Inf;        }        for(int i=1; i<=n; i++)        {            scanf("%d",&m);            while(m--)            {                scanf("%d%d",&j,&t);                mp[i][j]=t;            }        }        for(int i=1; i<=n; i++)            for(j=1; j<=n; j++)                for(t=1; t<=n; t++)                    if(mp[j][t]>mp[j][i]+mp[i][t])                        mp[j][t]=mp[j][i]+mp[i][t];        minn=Inf;        for(int i=1; i<=n; i++)        {            maxx=0;            for(int j=1; j<=n; j++)            {                if(j==i)                    continue;                if(mp[i][j]>maxx)                    maxx=mp[i][j];            }            if(maxx<minn)            {                minn=maxx;                t=i;            }        }        if(minn==Inf)            printf("disjoint\n");        else            printf("%d %d\n",t,minn);    }    return 0;}