luogu P2062 分队问题

版权声明：thanks for your copy! https://blog.csdn.net/weixin_43907802/article/details/88762479

analysis

肯定要先sort一次，不然毫无规律可循
然后就断篇了
好吧，看了题解后才发现其实并不难
然后就很好做了

code

#include<bits/stdc++.h>
using namespace std;
#define loop(i,start,end) for(register int i=start;i<=end;++i)
#define anri_loop(i,start,end) for(register int i=start;i>=end;--i)
#define clean(arry,num) memset(arry,num,sizeof(arry))
#define max(a,b) ((a>b)?a:b)
#define min(a,b) ((a<b)?a:b)
int n;
const int maxn=1000000+10;
int a[maxn];
int f[maxn];
template<class T>void read(T &x)
{
    x=0;char r=getchar();T neg=1;
    while(r>'9'||r<'0'){if(r=='-')neg=-1;r=getchar();}
    while(r>='0'&&r<='9'){x=(x<<3)+(x<<1)+r-'0';r=getchar();}
    x*=neg;
}
int main()
{
    #ifndef ONLINE_JUDGE
    freopen("datain.txt","r",stdin);
    #endif
    clean(a,0);
    clean(f,0);
    read(n);
    loop(i,1,n)read(a[i]);
    sort(a+1,a+1+n);
    loop(i,1,n)
    {
        if(i<a[i])
        {
            f[i]=f[i-1];
        }
        else if(i>=a[i])
        {
            f[i]=max(f[i-1],f[i-a[i]]+1);
        }
    }
    printf("%d",f[n]);
    return 0;
}