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HDOJ 4671 Backup Plan 构造优先队列

2024-08-03 20:43:48   216人阅读


优先队列构造前两列....

Backup Plan

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 775    Accepted Submission(s): 365
Special Judge

Problem Description
Makomuno has N servers and M databases. All databases are synchronized among all servers and each database has a ordered list denotes the priority of servers to access. This list is guaranteed to be a valid permutation of all servers.
Every time someone wants to execute queries on a certain database, he will send a request to the first server in the list. If it‘s dead, he will simply turn to the next one. Otherwise a working copy of the database is found, and this copy is called active.
Now, given N and M, Makomuno wants to find a permutation for each database which could assure that all servers are load-balanced. Moreover, Makomuno hopes the system will be load-balanced even if exactly one server is broken.
Note that if we call the number of active copies on i-th server Ai, then load-balanced means max∣Ai - Aj∣≤1 for any i and j in non broken servers set. We won‘t consider broken servers in this case.
 

Input
The input contains several test cases, terminated by EOF.
Each test case has one line containing two integer N ( 2≤N≤100) and M ( 1≤M≤100).
 

Output
For each case output M lines, the i-th line contains a permutation of all servers, indicating the expected order. Servers are numbered from 1 to n.
 

Sample Input
5 3
 

Sample Output
2 4 3 1 5
1 5 4 2 3
3 5 2 4 1

Hint

In the sample test case, the active copies of these databases are on server 2,1 and 3 in normal state. A = {1,1,1,0,0}
If server 1 or 3 has broken, server 5 will take its work. In case we lost server 2, the second database will use server 4 instead. A = {1,BROKEN,1,1,0}
It‘s clear that in any case this system is load-balanced according to the plan in sample output.
 

Source
2013 Multi-University Training Contest 7
 



#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <queue>

using namespace std;

int n,m;
int li[111][111];
bool have[111];

struct DUI
{
    int x,s;
    bool operator < (const DUI xx) const
    {
        return s>xx.s;
    }
};

int sum[111];

int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        for(int i=1;i<=n;i++)
        {
            sum[i]=m/n+((i<=m%n)?1:0);
        }

        for(int u=1;u<=n;u++)
        {
            priority_queue<DUI> q;
            for(int i=1;i<=n;i++)
            {
                if(i==u) continue;
                q.push((DUI){i,sum[i]});
            }
            for(int i=0;i<sum[u];i++)
            {
                int pos=u+i*n;
                DUI D=q.top(); q.pop();

                li[pos][1]=D.x;

                D.s++;
                q.push(D);
            }
        }



        for(int i=1;i<=m;i++)
        {
            int c=i;
            while(c>n) c-=n;
            li[i][0]=c;
        }

        for(int i=1;i<=m;i++)
        {
            memset(have,false,sizeof(have));
            have[li[i][0]]=true; have[li[i][1]]=true;
            int p=1;
            for(int j=2;j<n;j++)
            {
               while(have[p]==true) p++;
                li[i][j]=p;
                have[p]=true;
            }
        }


        for(int i=1;i<=m;i++)
        {
            for(int j=0;j<n;j++)
            {
                printf("%d%c",li[i][j],(j==n-1)?'\n':' ');
            }
        }
    }
    return 0;
}



HDOJ 4671 Backup Plan 构造优先队列


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