[{"createTime":1735734952000,"id":1,"img":"hwy_ms_500_252.jpeg","link":"https://activity.huaweicloud.com/cps.html?fromacct=261f35b6-af54-4511-a2ca-910fa15905d1&utm_source=V1g3MDY4NTY=&utm_medium=cps&utm_campaign=201905","name":"华为云秒杀","status":9,"txt":"华为云38元秒杀","type":1,"updateTime":1735747411000,"userId":3},{"createTime":1736173885000,"id":2,"img":"txy_480_300.png","link":"https://cloud.tencent.com/act/cps/redirect?redirect=1077&cps_key=edb15096bfff75effaaa8c8bb66138bd&from=console","name":"腾讯云秒杀","status":9,"txt":"腾讯云限量秒杀","type":1,"updateTime":1736173885000,"userId":3},{"createTime":1736177492000,"id":3,"img":"aly_251_140.png","link":"https://www.aliyun.com/minisite/goods?userCode=pwp8kmv3","memo":"","name":"阿里云","status":9,"txt":"阿里云2折起","type":1,"updateTime":1736177492000,"userId":3},{"createTime":1735660800000,"id":4,"img":"vultr_560_300.png","link":"https://www.vultr.com/?ref=9603742-8H","name":"Vultr","status":9,"txt":"Vultr送$100","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":5,"img":"jdy_663_320.jpg","link":"https://3.cn/2ay1-e5t","name":"京东云","status":9,"txt":"京东云特惠专区","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":6,"img":"new_ads.png","link":"https://www.iodraw.com/ads","name":"发布广告","status":9,"txt":"发布广告","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":7,"img":"yun_910_50.png","link":"https://activity.huaweicloud.com/discount_area_v5/index.html?fromacct=261f35b6-af54-4511-a2ca-910fa15905d1&utm_source=aXhpYW95YW5nOA===&utm_medium=cps&utm_campaign=201905","name":"底部","status":9,"txt":"高性能云服务器2折起","type":2,"updateTime":1735660800000,"userId":3}]
补充条件：m（arry存储）个里面选取n个。同时设置布尔数组（m个的）
以后统一设置前n个数组为1，用prev_permutation
例子：洛谷1249
#include<bits/stdc++.h> using namespace std; bool isnprimes[100000000];int
primes[10000000];int cnt,sum;int count1; int k,n; void ola(int n) { for(int
i=2;i<=n;i++) { if(isnprimes[i]==0)primes[++cnt]=i; for(int
j=1;i*primes[j]<=n;j++) { isnprimes[i*primes[j]]=1; if(i%primes[j]==0)break; }
} } int main() { scanf("%d%d",&n,&k); int arry[n+1]={0};for(int
i=1;i<=n;i++)scanf("%d",&arry[i]);int book[n+1]={0}; for(int
i=1;i<=k;i++)book[i]=1; ola(100000000); do { count1=0; for(int i=1;i<=n;i++){
if(book[i]==1)count1+=arry[i]; } if(isnprimes[count1]==0)sum++; }
while(prev_permutation(book+1,book+1+n)); printf("%d",sum); return 0; }
