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谁帮我看下哪错了In Reply To:请问有人能够将64的那组BT数据控制在1S之内么? Posted by:zentropy at 2007-09-02 16:03:34 所有数据都能通过,C++提交的时候一直出现RE错误,要崩溃了
#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<functional>
using namespace std;
bool search(int length,int p);
bool find(int l);
int wood[100],sol[200];//记录木棒信息,已用的木棒信息
bool use[100];//记录使用情况
int sum,key,n;//砍断后的木棒长度和,当前正在用的木棒,木棒总数
int main()
{
int i,total;
while (scanf("%d", &n) == 1, n)
{
memset(wood,0,sizeof(wood));
memset(sol,0,sizeof(sol));
memset(use,false,sizeof(use));
total=n;
sum=0;
for(i=0;i<total;i++)
{
scanf("%d",wood+i);
sum+=wood[i];
}
sort(wood,wood+total,greater<int>());//剪枝:将木棒长度从大到小排
if(sum%wood[0]==0&&find(wood[0]))
{
printf("%d\n",wood[0]);
}
else{
total/=2;//剪枝:因最长的木棒不合要求,故每根木棍至少由两根木棒合成
do{
while(sum/total<=wood[0])total--;
if(sum%total==0)
{
memset(use,false,sizeof(use));
if(find(sum/total)){printf("%d\n",sum/total);break;}
}
if(sum%2&&total==2){printf("%d\n",sum);break;}//剪枝:作用好像不太明显
}while(--total);
}
}
return 0;
}
bool find(int l)//验证该长度是否符合要求
{
int p,length,number;//当前指向的木棒,还缺的长度,应合成的数量
length=l;
number=sum/l;
key=1;
sol[0]=-1;
p=0;
while(--number)//剪枝:最后一根木棒不必验证
{
if(search(length,p))
{
sol[key++]=-1;
length=l;
p=0;
}
else{
number+=2;
key--;
p=sol[key]+1;
length=wood[sol[key]];
use[sol[key]]=false;
sol[key]=0;
if(number>sum/l||key<=1)return false;
}
}
return true;
}
bool search(int length,int p)
{
int i=p;
while(length)
{
while(wood[i]>length||use[i]||i==n)//找到比剩余长度小且未被使用过的木棒
{
if(i==n)
{
key--;
length+=wood[sol[key]];
use[sol[key]]=false;
i=sol[key];
sol[key]=0;
while(wood[i]==wood[i+1])i++;
//剪枝:因该长度不合要求,故找下一根不同长度的木棒(很重要)
if(sol[key-1]==-1){sol[--key]=0;return false;}
}
i++;
}
length-=wood[i];
use[i]=true;
sol[key++]=i;
i++;
}
return true;
}
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