HIT暑期集训Day4 搜索

#include<cstdio>
#include<cmath>
#define inf 0x3f3f3f3f
using namespace std;
int n,m,ans,sumv[25],sums[25];
void dfs(int lr,int lh,int res,int num,int s)
{
    if (num==0)
    {
        if (res==0 && s<ans) ans=s;
        return;
    }
    if (sumv[num]>res || sums[num]+s>ans) return;
    if (res<0 || 2*res/lr+s>ans) return;    
    int i,j,tmp;
    for (i=lr;i>=num;i--)
    {
        tmp=(res-sumv[num-1])/(i*i);
        if (lh<tmp) tmp=lh;
        for (j=tmp;j>=num;j--)
        {
            if (i*i*j>res) break;
            if (num==m) dfs(i-1,j-1,res-i*i*j,num-1,s+2*i*j+i*i); 
            else dfs(i-1,j-1,res-i*i*j,num-1,s+2*i*j);
        }
    }
}
int main()
{
    int i;
    sumv[0]=0;sums[0]=0;
    for (i=1;i<=20;i++) 
    {
        sumv[i]=sumv[i-1]+i*i*i;
        sums[i]=sums[i-1]+2*i*i;
    }
    while (scanf("%d%d",&n,&m)!=EOF)
    {
        ans=inf;
        dfs(n,n,n,m,0);
        if (ans==inf) printf("0
");
        else printf("%d
",ans);
    }
    return 0;
 }

View Code

C HDU 1043

D POJ 1011

#include<cstdio>
#include<algorithm>
using namespace std;
int a[70],vis[70],n,flag;
void dfs(int num,int res,int x,int last)
{
    if (num==0 && res==0)
    { 
        flag=1;return;
    } 
    if (num==0 || flag) return;
    if (res==0) res=x,last=n;
    for (int i=last;i>=1;i--)
    {
        if (i!=n && a[i]==a[i+1] && !vis[i+1]) continue;
        if (a[i]>res || vis[i]) continue;
        vis[i]=1;
        dfs(num-1,res-a[i],x,i-1);
        vis[i]=0;
        if (res==a[i] || res==x) return;
    }
}
int main()
{
    int i,sum;
    while (scanf("%d",&n)!=EOF && n!=0)
    {
        sum=0;
        for (i=1;i<=n;i++) 
        {
            scanf("%d",&a[i]);
            sum+=a[i];
        }
        sort(a+1,a+n+1);
        for (i=a[n];i<=sum;i++)
        {
            if (sum%i!=0) continue;
            flag=0;
            dfs(n,i,i,n);
            if (flag) break;
        }
        printf("%d
",i);
    }
    return 0;
 }

View Code

F Gym 101933E

H POJ 1167

I CodeForces 60C