Venue arrangement Questions

Description

Suppose you want to arrange a number of events in enough venues and want to use as few venues as possible. Design an effective greedy algorithm for scheduling. ( This problem is actually a well-known graph coloring issue.) If each activity is a vertex of the graph , the incompatible activities are connected by edges. Causes the adjacent vertices to have a minimum number of colors, corresponding to the minimum number of venues to find . )

Requirement: For a given K to be scheduled activities, the programming calculates the minimum venue schedule.

Input

    input data 1  a positive integer k (k<=10000) k k 2 k 0 

Output

The output data is 1 rows, indicating the minimum number of venues calculated.

Sample Input5 1 (+)Sample Output3

Idea: greedy, first sort all activities according to the start time, then mark the adjacent non-coincident activities in turn. The number of times to go back and forth is the amount of venues needed. Note: The start time of an activity can be exactly the end time of the previous activity.

Code:

#include <iostream>#include<vector>#include<stdlib.h>#include<algorithm>using namespacestd;classactivity{ Public:    intstart; intend; BOOLprocessed; Activity (intStartintEndBOOLProcessed=false){         This->start=start;  This->end=end;  This->processed=processed; }};BOOLcmpConstActivity & A,ConstActivity &b) {    returnB.start>A.start;}intGreedy (vector<activity>activities) {    intlen=activities.size (); intret=0;  while(1){        BOOL Get=false;  for(intI=0; i<len;i++){            intTime ; if(!activities[i].processed) {ret++; time=Activities[i].end; Activities[i].processed=true; }             for(intj=i+1; j<len;j++){                if(!activities[j].processed&&activities[j].start>=Time ) {activities[j].processed=true; time=Activities[j].end; }            }        }        if(!Get)             Break; }    returnret;}intMainintargcChar**argv) {    intN; CIN>>N; Vector<activity>activities;  for(intI=0; i<n;i++){        intstart; intend; CIN>>start>>end; Activity Temp=activity (start,end);    Activities.push_back (temp);    } sort (Activities.begin (), Activities.end (), CMP); cout<<greedy (Activities) <<Endl;}

Venue arrangement Questions