void tryput(int i, int bthis, int rstart, int wasted) {
if (i > maxput) maxput = i;
if (maxput == optimal) return;
if (wasted > bwasted[maxput + 1]) return;
int rlast = 0;
bool tried = false;
for (int j = rstart; j < r; j++) {
if (railused[j]) continue; // already used
int rlen = rail[j];
if (rlen == rlast) continue; // same length only try once
rlast = rlen;
if (rlen > b[bthis] - bused[bthis]) continue; // space left not enough
if (bthis > 0 && rlen + bused[bthis] > b[bthis - 1]) continue;
railused[j] = true;
bused[bthis] += rlen;
tryput(i + 1, bthis, j + 1, wasted);
tried = true;
bused[bthis] -= rlen;
railused[j] = false;
}
if (!tried) {
if (bthis + 1 < n) {
tryput(i, bthis + 1, 0, wasted + b[bthis] - bused[bthis]);
}
}
}
//a数组存放已得到的序列，usd[k] 表示值是否被使用
int main()
{
int k,m;
while(1)
{
for(k=1;k<=20;k++)
{//初始化
a[k]=0;
used[k]=0;
}
scanf("%d",&m);
if(m == 0)//输入 0 结束
break;
a[1]=m;
used[m]=1;//第一个数为m，且标记被使用
tryput(2);
for(k=1;k<=20;k++)
printf("%d ",a[k]);
printf("\n");
}
}
void writeOut() {
qsort(b, n, sizeof(int), icmpn);
qsort(rail, r, sizeof(int), icmp);
int bsum = 0;
for (int i = 0; i < n; i++) {
bleft[i] = b[i];
bused[i] = 0;
bsum += b[i];
}
bwasted[0] = bsum;
optimal = 0;
for (int i = 0; i < r; i++) {
if (bsum >= rail[i]) {
bsum -= rail[i];
optimal++;
bwasted[optimal] = bsum;
} else {
break;
}
}
r = optimal;
qsort(rail, r, sizeof(int), icmpn);
for (int i = 0; i < r; i++) {
railused[i] = false;
}
maxput = 0;
tryput(0, 0, 0, 0);
fout = fopen("fence8.out", "w"); assert(fout);
fprintf(fout, "%d\n", maxput);
fclose(fout);
}
int tryput(int i)//搜索第i项的数
{
int j;
for(j=1;j<=20;j++)//1~20项中查找
{
if(used[j])//如果被使用，查找下一个
continue;
if(sumisprime(j,i))//是否满足条件
{
a[i]=j;
used[j]=1;//若满足，则保留此数并标记
if(i==20)
return 1;//20项查找完，正确返回
if(tryput(i+1) != 1)//若第i+1项查找不成功，回溯
{
a[i]=0;
used[j]=0;
}
else
return 1;//若成功，则返回1
}
}
return 0;
}
