PKU poj-1011

Stick

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 136132		Accepted: 32036

Description

George brought a set of equal-length sticks and cut them randomly, making each stick less than 50 units in length. He then tried to restore the sticks to a pre-cut state, but forgot how many sticks and the initial lengths of the sticks were initially. Please design a program to help George calculate the possible minimum length of the stick. The length of each stick is represented by an integer greater than 0.

Input

The input contains multiple sets of data, each of which consists of two rows. The first line is an integer that does not exceed 64, indicating how many sticks are in total after the chop. The second line is truncated after the length of each section of the stick. After the last set of data, it is a zero.

Output

For each set of data, output the smallest possible length of the original stick, one row for each group of data.

Sample Input

95 2 1 5 2 1 5 2 141 2 3 40

Sample Output

65

Source

Central Europe 1995 Method: dfs+ Strong pruning Analysis: Classic search problems, need to carefully consider the pruning conditions, each time the pruning can greatly improve the speed. Pruning: 1. First, the data from the big to the small sort, the search time from large to small search, so as to ensure the full use of data, and pruning is also very helpful 2. The length of the original bar is approximate to the total length, so the search space is approximate 3 of the total length. When retrieving, use the length of the longest bar as the starting length of the search 4. If stick[i] = = Stick[i+1], and Stick[i] match fails, then stick[i+1] must also be a failure of 5. If the first bar of group I (also the longest) fails during the matching process, then the I-1 group is returned directly to the re-match. Because the combination of group I must be a subset of the longest wood bars.

1#include <stdio.h>2#include <stdlib.h>3#include <string.h>4 5 #defineMax_num 646 #defineFAILURE 17 #defineSUCCESS 08 9 intGwsticknum =1;Ten intGwtotallen; One intGwdata[max_num]; A intGwselect[max_num]; - intGwgroup; -  the voidSortint*a,intLeftintRight ) - { -     if(Left >=Right ) -     { +         return; -     } +     inti =Left ; A     intj =Right ; at     intKey =A[left]; -      while(I <j) -     { -          while(I<j && key>=A[j]) -         { -j--; in         } -A[i] =A[j]; to          while(I<j && key<=A[i]) +         { -i++; the         } *A[J] =A[i]; $     }Panax NotoginsengA[i] =key; -Sort (A, left, I-1); theSort (A, i+1, right); + } A  the intMatchintGoalintSumintNowgroup) + { -     inti =0; $     if(Sum > Goal)returnFAILURE; $     if(Sum = =goal) -     { -nowgroup++; the         if(Nowgroup = = Gwgroup)returnSUCCESS; -sum =0;Wuyi         returnmatch (goal, sum, nowgroup); the     } -      for(i=1; i<gwsticknum; i++) Wu     { -         if(Gwselect[i] = =1)Continue; AboutSum + =Gwdata[i]; $Gwselect[i] =1; -         if(SUCCESS = = Match (goal, SUM, Nowgroup))returnSUCCESS; -Gwselect[i] =0; -Sum-=Gwdata[i]; A         if(Sum = =0)returnFAILURE; +          while(Gwdata[i] = = gwdata[i+1] && I <gwsticknum) the         { -i++; $         } the     } the     returnFAILURE; the } the  - intSearchfactors (intstart) in { the     inti =0; the      for(i=start+1; i<=gwtotallen; i++) About     { the         if(gwtotallen% i = =0)returni; the     } the     return 0; + } -  the intCalc ()Bayi { the     intsum = gwdata[0]; the     intLen =0; -gwselect[0] =1; -     intStart = gwdata[0]-1; the      while(Start <Gwtotallen) the     { theLen =searchfactors (start); theGwgroup = Gwtotallen/Len; -         if(SUCCESS = = Match (Len, Sum,0))returnLen; theStart =Len; thememset (Gwselect,0,sizeof(Gwselect)); thegwselect[0] =1;94sum = gwdata[0]; the     } the     return 0; the }98  About intGettatollen (int*a,intArrylen) - {101     inti =0;102     intsum =0;103      for(i=0; i<arrylen; i++)104     { theSum + =A[i];106     }107     returnsum;108 }109  the intMainvoid)111 { the     inti =0;113     intresult =0; the      while(SCANF ("%d", &gwsticknum), gwsticknum! =0) the     { the          for(i=0; i<gwsticknum; i++)117         {118scanf"%d", &gwdata[i]);119         } - 121Gwtotallen =Gettatollen (Gwdata, gwsticknum);122Sort (Gwdata,0, gwsticknum-1);123result =Calc ();124  theprintf"%d\n", result);126memset (Gwselect,0,sizeof(Gwselect));127     } - 129     return 0; the}

Test data: 915 3 2 8 8 4 each 8 1020------------------------------------------------------2715 3 2 4 11 1 8 8 8 15 3 2 4 11 1 8 8 8 3 2 4 1 8 8 8020------------------------------------------------------2 1 5 2 1 5 2 141 2 3 4065--------------- ---------------------------------------4640 37 32 10 47 4 42 56 61 23 59 36 27 16 16 37 26 19 14 29 31 58 51 32 63 28 11 2 5 12 15 39 42 46 43 11 19 53 17 39 21 45 44 8 23 51 55 5857 6 44 4 16 35 54 9 32 23 43 55 46 41 8 41 55 44 31 59 57 58 59 29 53 30 3 39 52 17 32 45 8 40 34 18 20 11 32 33 14 41 31 25 4 42 54 9 29 37 47 29 34 20 47 56 61 5 263 64 18 49 4 40 18 6 1 50 36 17 49 8 17 62 11 24 8 36 59 34 26 28 7 37 26 0898999

PKU poj-1011