HUNNU-10307-最优分解问题

点击打开题目连接

# include <queue>
# include <cstdio>
# include <cstring>
# include <iostream>
# include <algorithm>
using namespace std;

int v[4] = {1,10,100,1000},a[100000];

struct BigNumber{
    int d[1000];
    BigNumber() { memset(d,0,sizeof(d));    d[0] = 1; }
    BigNumber operator =(const int b){
        char s[40];
        sprintf(s,"%d",b);
        int len = strlen(s);
        memset(d,0,sizeof(d));
        d[0] = (len - 1)/4 + 1;
        for(int i = 0;i < len;i++)  d[(len-i-1)/4+1] += (s[i]-'0')*v[(len-i-1)%4];
        return *this;
    }
    void put(){
        printf("%d",d[d[0]]);
        for(int i = d[0]-1;i >= 1;i--)  printf("%04d",d[i]);
        printf("\n");
    }
};

BigNumber operator * (const BigNumber &a,const int &k)
{
    BigNumber c;
    c.d[0] = a.d[0];
    int i ,x = 0;
    for(int i = 1;i <=a.d[0];i++){
        x = a.d[i]*k + x;
        c.d[i] = x%10000;
        x /= 10000;
    }
    while(x > 0){
        c.d[++c.d[0]] = x%10000;
        x /= 10000;
    }
    while((c.d[0]>1) && (c.d[c.d[0]] == 0)) --c.d[0];
    return c;
}

int main()
{
    //freopen("a.txt","r",stdin);
    //freopen("b.txt","r",stdin);
    __int64 n,i;
    while(~scanf("%I64d",&n)){
        BigNumber ans;
        ans = 1;
        if(n <= 4){
            printf("%d\n",n);   continue;
        }
        //算出n的连续和;
        for(i = 2;i < n;i++){
            a[i-2] = i;
            n -= i;
        }
        
        int cnt = i - 3;
        while(n){
            a[cnt]++;
            n--;
            cnt -= 1;
            if(cnt == -1)   cnt = i - 3;
        }
        for(int j = 0;j <= i - 3;j++){
            //printf("%d ",a[j]);
            ans = ans * a[j];
        }
        ans.put();
    }
    return 0;
}