A - Dividing
Time Limit:1000MS Memory Limit:32768KB 64bit IO Format:%I64d
& %I64u
Submit Status
Description
Marsha and Bill own a collection of marbles. They want to split the collection among themselves so that both receive an equal share of the marbles. This would be easy if all the marbles had the same value, because then they could
just split the collection in half. But unfortunately, some of the marbles are larger, or more beautiful than others. So, Marsha and Bill start by assigning a value, a natural number between one and six, to each marble. Now they want to divide the marbles so
that each of them gets the same total value.
Unfortunately, they realize that it might be impossible to divide the marbles in this way (even if the total value of all marbles is even). For example, if there are one marble of value 1, one of value 3 and two of value 4, then they cannot be split into sets
of equal value. So, they ask you to write a program that checks whether there is a fair partition of the marbles.
Input
Each line in the input describes one collection of marbles to be divided. The lines consist of six non-negative integers n1, n2, ..., n6, where ni is the number of marbles of value i. So, the example from above would be described
by the input-line ``1 0 1 2 0 0‘‘. The maximum total number of marbles will be 20000.
The last line of the input file will be ``0 0 0 0 0 0‘‘; do not process this line.
Output
For each colletcion, output ``Collection #k:‘‘, where k is the number of the test case, and then either ``Can be divided.‘‘ or ``Can‘t be divided.‘‘.
Output a blank line after each test case.
Sample Input
1 0 1 2 0 0 1 0 0 0 1 1 0 0 0 0 0 0
Sample Output
Collection #1: Can‘t be divided. Collection #2: Can be divided.
多重背包
m = -1 ;
while( (1<<(m+1) )-1 < a[i] )
m++ ;
得到m值，对应2^0 , 2^1, 。。2^(m-1) , a[i] - 2^m+1 ;优化每个组的数量
#include <cstdio>
#include <cstring>
#include <algorithm>
int a[10] ;
int dp[200000] ;
int main()
{
int ans , i , j , k , t = 0 , m , s ;
while( scanf("%d", &a[1]) )
{
t++ ;
ans = a[1]*1 ;
for(i = 2 ; i <= 6 ; i++)
{
scanf("%d", &a[i]);
ans += a[i]*i ;
}
if(ans == 0)
break;
printf("Collection #%d:\n", t );
if( ans%2 )
{
printf("Can't be divided.\n\n");
continue ;
}
ans /= 2 ;
memset(dp,0,sizeof(dp));
dp[0] = 1 ;
for(i = 1 ; i <= 6 ; i++)
{
m = -1 ;
while( (1<<(m+1) )-1 < a[i] )
m++ ;
for(j = 0 ; j <= m ; j++)
{
if(j == m) s = a[i] - (1<<j) + 1 ;
else s = 1<<j ;
for(k = ans ; k >= i*s ; k--)
{
if( !dp[k] && dp[k- (i*s) ] )
dp[k] = 1 ;
if( dp[ans] )
break;
}
if( dp[ans] )
break;
}
if( dp[ans] )
break;
}
if( dp[ans] )
printf("Can be divided.\n\n");
else
printf("Can't be divided.\n\n");
}
return 0;
}