POJ-1011

 深搜，剪枝

这组数据用的时间应该超过一秒了，可提交还是AC了。

数据：

64
40 40 30 35 35 26 15 40 40 40 40 40 40 40 40 40 40 40 40 40 40 

40 40 43 42 42 41 10 4 40 40 40 40 40 40 40 40 40 40 40 40 40 

40 25 39 46 40 10 4 40 40 37 18 17 16 15 40 40 40 40 40 40 40 

40

#include <iostream>

using namespace std;

 

int n,a[64],mark[64],totalLen,sLen;

 

void kSort(int low,int high)

{

int pivotkey = a[low],i = low, j=high;

while(i < j){

while(i<j && a[j] <= pivotkey)

j--;

a[i] = a[j];

while(i<j && a[i] >= pivotkey)

i++;

a[j] = a[i];

}

a[i] = pivotkey;

if(low < high){

kSort(low,i-1);

kSort(i+1,high);

}

}

bool dfs(int temp, int k, int num)

{

if(num == totalLen/sLen) return true;

else if(temp == sLen)

dfs(0,0,num+1);

else{

int i,pre=0;// ?????

for(i=k; i<n; i++) 

if(mark[i]==0 && a[i] != pre && a[i] + temp <= sLen){

mark[i] = 1;

pre = a[i];

if(dfs(temp+a[i],i+1,num))

break;

mark[i] = 0;

if(k==0)

return false;

  }

// cout << pre << endl;

if(i==n)

return false;

else

return true;

}

}

int main()

{

int i;

scanf("%d",&n);

while(n){

totalLen = 0;

memset(a,0,sizeof(a));

memset(mark,0,sizeof(mark)); // mark 大小

for(i=0; i<n; i++){

scanf("%d",&a[i]);

totalLen += a[i];

}

kSort(0,n-1);

sLen = a[0];

while(sLen <= totalLen){

while(totalLen % sLen)

sLen++;

if(dfs(0,0,0)){

printf("%d/n",sLen);

break;

}

memset(mark,0,sizeof(mark));

sLen++;

}

scanf("%d",&n);

}

return 0;

}