poj2923 01背包+状态压缩dp

http://poj.org/problem?id=2923

Description

Emma and Eric are moving to their new house they bought after returning from their honeymoon. Fortunately, they have a few friends helping them relocate. To move the furniture, they only have two compact cars, which complicates everything a bit. Since the furniture does not fit into the cars, Eric wants to put them on top of the cars. However, both cars only support a certain weight on their roof, so they will have to do several trips to transport everything. The schedule for the move is planed like this:

1. At their old place, they will put furniture on both cars.
2. Then, they will drive to their new place with the two cars and carry the furniture upstairs.
3. Finally, everybody will return to their old place and the process continues until everything is moved to the new place.

Note, that the group is always staying together so that they can have more fun and nobody feels lonely. Since the distance between the houses is quite large, Eric wants to make as few trips as possible.

Given the weights w_i of each individual piece of furniture and the capacities C₁ and C₂ of the two cars, how many trips to the new house does the party have to make to move all the furniture? If a car has capacity C, the sum of the weights of all the furniture it loads for one trip can be at most C.

Input

The first line contains the number of scenarios. Each scenario consists of one line containing three numbers n, C₁ and C₂. C₁ and C₂ are the capacities of the cars (1 ≤ C_i ≤ 100) and n is the number of pieces of furniture (1 ≤ n ≤ 10). The following line will contain n integers w₁, …, w_n, the weights of the furniture (1 ≤ w_i ≤ 100). It is guaranteed that each piece of furniture can be loaded by at least one of the two cars.

Output

The output for every scenario begins with a line containing “Scenario #i:”, where i is the number of the scenario starting at 1. Then print a single line with the number of trips to the new house they have to make to move all the furniture. Terminate each scenario with a blank line.

Sample Input

26 12 133 9 13 3 10 117 1 1001 2 33 50 50 67 98

Sample Output

Scenario #1:2Scenario #2:3

/**题意：    两个车有容量a与b，n个物品，每个物品有一个体积，问最小多少次能够运完他们。因为n<10，所以可以用状态压缩。先进行遍历，看看1<<n这些状态能不能一次运完。能的话加入it数组里。然后用it数组，代表物品，进行背包 j代表状态，!(j&it[i])时，代表两个状态不冲突，就是不存在某个物品运了两次。j|it[i]代表当前状态。*/#include <stdio.h>#include <string.h>#include <iostream>#include <algorithm>using namespace std;const int N=1<<10+1;const int INF=0x3f3f3f3f;int dp[N],g[N],weg[11];bool vis[N];int n,c1,c2,s;bool judge(int x){    int sum=0;    memset(vis,0,sizeof(vis));    vis[0]=1;    for(int i=0; i<n; i++)        if(x&(1<<i))        {            sum+=weg[i];            for(int j=c1-weg[i]; j>=0; j--)                if(vis[j])                    vis[j+weg[i]]=1;        }    for(int i=0; i<=c1; i++)        if(vis[i]&&sum-i<=c2)            return true;    return false;}int main(){    int T,tt=0;    cin >> T;    while(T--)    {        scanf("%d%d%d",&n,&c1,&c2);        for(int i=0; i<n; i++)            scanf("%d",&weg[i]);        s=0;        for(int i=1; i<1<<n; i++)        {            if(judge(i))                g[s++]=i;        }        for(int i=(1<<n)-1; i>0; i--)            dp[i]=INF;        dp[0]=0;        for(int i=0; i<s; i++)        {            for(int j=0; j<(1<<n); j++)                if(!(j&g[i]))                    dp[j|g[i]]=min(dp[j|g[i]],dp[j]+1);        }        printf("Scenario #%d:\n%d\n\n",++tt,dp[(1<<n)-1]);    }    return 0;}