Ker_White @ 2024-07-16 10:49:49
#include<bits/stdc++.h>
#define homo 114514
using namespace std;
int a[homo],l,r,n,sum=0,Mdata[homo],ts=0,b;
bool vis[homo];
void dfs(int x) {
if(x == r+1) {
ts=0;
for(int i=1;i<=r;i++)
{
ts+=Mdata[a[i]];
}
if(ts>=l && ts<=b)
{
sum++;
}
return;
}
for(int i = a[x-1]+1; i<= n; i++) {
if(vis[i] == false) {
a[x] = i;
vis[i] = true;
dfs(x+1);
vis[i] = false;
}
}
return;
}
int main()
{
cin>>n>>l>>b;
for(int i=1;i<=n;i++)
{
cin>>Mdata[i];
ts+=Mdata[i];
if(Mdata[i]>=l && Mdata[i]<=b)
{
sum++;
}
}
if(ts>=l && ts<=b)
{
sum++;
}
for(int i=2;i<=n-1;i++)
{
r=i;
dfs(1);
}
cout<<sum;
return 0;
}by switchwanjia @ 2024-09-15 17:25:15
#include<bits/stdc++.h>
using namespace std;
int n,l,r,w[1000],ans=0;
void search(int p,int sum)
{
if(sum>r)
return;
if(p>n)
{
if(sum>=l&&sum<=r)
ans++;
return;
}
search(p+1,sum);
search(p+1,sum+w[p]);
}
int main()
{
ios::sync_with_stdio(0);
cin>>n>>l>>r;
for(int i=1;i<=n;++i)
cin>>w[i];
search(1,0);
cout<<ans;
return 0;
}
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