poj1011 深搜题代码解释

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int n;
int stick[100];
int total;
int ns;
int ok;
int len;
int used[100];

int cmp(const void *a,const void *b) {
   int a1 = *(int *)a;
   int a2 = *(int *)b;
   return a2 - a1;
} 

int adds() {
   int j = 0;
   for (int i = 1;i <= n;i++)
      j += stick[i];
   return j;
}

void search(int,int,int);

void s(int x) {
   if (x > ns) {
      ok = 1;
      printf("%d/n", len);
      return;
   }

   int i;
   for (i = 1;i <= n;i++)
      if (!used[i]) break;

   used[i] = 1;
   search(x,stick[i],i);
   used[i] = 0;
}

void search(int num,int now,int next) {

   if (ok) return;
   if (now == len) {
       s(num + 1);
    return;
   }

   if (next + 1 > n) return;

   for (int i = next + 1;i <= n;i++)
      if (!used[i])
       if(stick[i] + now <= len) {
         used[i] = 1;
         search(num,now + stick[i],i);
         used[i] = 0;
         if (ok) return;
         if (stick[i] == len - now) return; 
       }
}

int main() {
   while (scanf("%d", &n) == 1) {
       if (!n) break;
       ok = 0;
       
    int i;
    for (i = 1;i <= n;i++) scanf("%d", &stick[i]);
    qsort(stick+1,n,sizeof(int),cmp);
    total = adds();
    for (i = stick[1];i <= total;i++)
        if (total % i == 0 && !ok) {
            ns = total / i;
            memset(used,0,sizeof(used));
            len = i;
            s(1);
        }
   }
   return 0;
}