HDU 4277 USACO ORZ

2012长春网络赛1011题

 

暴力枚举+map判重+Hash标记

 

 

代码：

#include <stdio.h>
#include <string.h>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
using namespace std;

const int N=15;

int a[N];
int tot;
int sum[1<<N];
int T,n;
int ubd;

bool vis[160010];
bool visi[160010];


struct Tri{
    int a,b,c;
    Tri();
    Tri(int aa,int bb,int cc){a=aa,b=bb,c=cc;}
    bool operator<(const Tri &x) const {
        if(a!=x.a) return a<x.a;
        if(b!=x.b) return b<x.b;
        return c<x.c;
    }
};

set<Tri> s;


bool istri(int a,int b,int c){
    return a+b>c && b+c>a && a+c>b && a>=b && b>=c && a!=0 && b!=0 && c!=0;
}




int main() {
    scanf("%d",&T);
    while(T--){
        memset(vis,0,sizeof(vis));
        memset(visi,0,sizeof(visi));
        s.clear();
        scanf("%d",&n);
        tot=0;
        for(int i=0;i<n;i++) scanf("%d",&a[i]),tot+=a[i];
        for(int i=0;i<1<<n;i++) {
            sum[i]=0;
            for(int j=0;j<n;j++) if(i&(1<<j)) sum[i]+=a[j];
        }

        for(int i=1;i<1<<n;i++) {
            int submask=(1<<n)-1;
            int mask=i^submask;
            if(sum[i]>=sum[mask] || mask==0) continue;

            for (int sub = (mask-1)&mask; sub != 0; sub = (sub - 1) & mask) {
                if(!vis[sum[sub]]&&istri(sum[i],sum[sub],sum[sub^mask])){
                    vis[sum[sub]]=1;
                    s.insert(Tri(sum[i],sum[sub],sum[sub^mask]));
                }
            }
            for (int sub = (mask-1)&mask; sub != 0; sub = (sub - 1) & mask) {
                vis[sum[sub]]=0;
            }
        }

        printf("%d\n",s.size());
    }
    return 0;
}