hdu 1455 sticks

#include "iostream"
#include "algorithm"
#include "memory.h"
using namespace std;

int sticks[64],n,len,num;
bool used[64];

bool cmp(int a,int b)
{
return a > b;
}

bool dfs(int cur,int left,int level)
{  //cur: 当前已经计算的木棒编号，left:该段还剩的长度，level:已经成功的木棒数
if (left == 0) {//匹配一根木棒成功
if (level == num-2)  return true;
for (cur = 0; used[cur];cur++);//找到下一个未访问过的长度
used[cur] = true;
if (dfs(cur+1,len-sticks[cur],level+1))
return true;
used[cur] = false;              //回溯
return false;
} else {
if (cur >= n-1) return false;
for (int i = cur;i < n; ++ i) {//剪枝
if (used[i]) continue;      //访问过的长度
if (sticks[i] == sticks[i-1] && !used[i-1]) continue; //相等的长度已经搜过的不搜
if (sticks[i] > left) continue;                     //大于达到len的生育长度
used[i] = true;
if (dfs(i,left-sticks[i],level)) return true;
used[i] = false;        //回溯
}
return false;
}
}
int main()
{
while (cin >> n,n) {
int sum = 0;
for (int i = 0;i < n; ++ i) {
cin >> sticks[i];
if(sticks[i]>50)
{
n--;i--;continue;
}
sum += sticks[i];
}
sort(sticks,sticks + n,cmp);//剪枝
bool end = false ;
for (len = sticks[0]; len <= sum/2; len++) {
if (sum%len == 0) {     //剪枝
used[0] = true;
num = sum/len;
if (dfs(0,len-sticks[0],0)) {
end = true;
cout << len << endl;
break;
}
used[0] = false;    //回溯
}
}
if (!end) cout << sum << endl;
memset(used,0,sizeof(used));
}
return 0;
}