Poj1548--robots

Robots

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 4037		Accepted: 1845

Description

Your Company provides robots, can be used to pick up litter from fields after sporting events and concerts. Before robots was assigned to a job, an aerial photograph of the field was marked with a grid. Each of the contains garbage is marked. All robots begin with the northwest corner and end their movement in the southeast corner. A robot can only move in and directions, either to the East or south. Upon entering a cell that contains garbage, the robot would pick it up before proceeding. Once a robot reaches its destination at the southeast corner it cannot be repositioned or reused. Since your expenses is directly proportional to the number of robots used for a particular job, you is interested in fin Ding the minimum number of robots so can clean a given field. For example, consider the field map shown in Figure 1 with rows and columns numbered as shown and garbage locations marked With a ' G '. In this scheme, the all robots would begin in the location of the and end in Location 6, 7. 

Figure 1-a Field Map
Figure 2 below shows-possible solutions, the second of which is preferable since it uses both robots rather than three.

Figure 2-two Possible Solutions
Your task is to create a program that would determine the minimum number of robots needed to pick up all the garbage from a Field.

Input

The input consists of one or more field maps followed by a line containing-1-1 to signal the end of the input data. A field map consists of one or more lines, each containing one garbage location, followed by a line containing 0 0 to sign Al the end of the map. Each garbage location consists of both integers, the row and column, separated by a single space. The rows and columns is numbered as shown in Figure 1. The garbage locations is given in row-major order. No single field map would have the more than rows and columns. The sample input below shows an input file with a field maps. The first is the field map from Figure 1.

Output

The output would consist of a single line for each field map containing the minimum number of robots needed to clean the CO rresponding field.

Sample Input

1 21 42 42 64 44 76 60 01 12 24 40 0-1-1

Sample Output

2 1

Source

Mid-Central USA 2003//mainly find out the key meaning; as long as the existence of the minimum number of partitions so that each partition within the two-tuple will meet X1 <= x2 and y1 <= y2: Dirworth theorem

1#include <stdio.h>2#include <algorithm>3 using namespacestd;4 5 structField6 {7     inth;8     intZ;9 } ;TenField num[ -] ; One  A BOOLcmp (field H,field z)/* - { -     if(H.H = =z.h) the     returnH.z <z.z; -     Else -     returnH.H <z.h; /* - } +  -  + intMain () A { at     intm,n,i; -      while(~SCANF ("%d%d", &num[0].h, &num[0].Z), (num[0].h!=-1, num[0].z!=-1)) -     { -          for(i=1;; i++) -         { -scanf"%d%d", &num[i].h, &num[i].z); in             if(!num[i].h,!)num[i].z) -              Break; to         } +Sort (num, num+I, CMP); -         intTemp, J, K, total=0 ; the          for(j=0; j<i; J + +*/* Not first traverse, after statistics! 0 numbers, not optimal; *         { $             if(Num[j].z! =0)Panax Notoginseng             { -temp =num[j].z; thetotal++; +                  for(k=j+1; k<i; k++) A                 { the                     if(Num[k].z >=temp) +                     { -temp=num[k].z; $Num[k].z =0 ; $                     } -                 } -             } the              -         }                                /*Wuyiprintf"%d\n", total); the     } -     return 0 ; Wu}

Poj1548--robots