求助

CSP_Sept @ 2020-03-08 10:38:27

#include <cstdio>
#include <iostream>

using namespace std;
int n;
int a1,a2,a3,minn;
bool flag=1;
int main(){
    freopen("order.in","r",stdin);
    freopen("order.out","w",stdout);
    scanf("%d",&n);
    for(int a=0;a<n/7;a++){
        for(int b=0;b<n/4;b++){
            int c=(n-a*7-b*4)/3;
            if(7*a+4*b+3*c==n&&flag) flag=0,a1=a,a2=b,a3=c,minn=min(min(a,b),c);
            else if(7*a+4*b+3*c==n&&!flag){
                if(min(min(a,b),c)>minn) a1=a,a2=b,a3=c,minn=min(min(a,b),c);
                else if(min(min(a,b),c)==minn){
                    if(a+b+c>a1+a2+a3) a1=a,a2=b,a3=c,minn=min(min(a,b),c);
                }
            }
        }
    }
    if(!flag) printf("%d %d %d",a1,a2,a3);
    else printf("-1");
    return 0;
}

by YUYGFGG @ 2020-03-08 10:40:00

@CSP_Sept 这题是数论

by _Herobrine_ @ 2020-03-08 10:40:11

我跟你一样

by CSP_Sept @ 2020-03-08 10:40:38

预计得分 50+10+0=60

by Hexarhy @ 2020-03-08 10:40:45

@CSP_Sept 优化常数。

把除改为乘，然后加register

我都AC了，同样的解法不开O2最慢800ms，开了300ms

by Alarm5854 @ 2020-03-08 10:40:47

@CSP_Sept 这个可以打一个 14\times3 的表（我就是这么做的）

by _Herobrine_ @ 2020-03-08 10:40:57

#include<bits/stdc++.h>
using namespace std;
int main()
{
    //freopen("order.in","r",stdin);
    //freopen("order.out","w",stdout);
    int n;
    cin>>n;
    if(n<3) {cout<<-1;return 0;}
    int ans1,ans2,ans3,f=0,a,b,c,z1=-1,z2=-1,y1=0,y2=0;
    for(c=0;c*3<=n;c++)
    {
        for(b=0;b*4+c<=n;b++)
        {
            a=(n-c*3-b*4)/7;
            if(c*3+b*4+a*7==n)
            {
                y1=min(min(a,b),c);
                y2=a+b+c;
                if(y1>z1)
                {
                    z1=y1;
                    z2=y2;
                    ans1=a;
                    ans2=b;
                    ans3=c;
                }
                else if(y1==z1)
                {
                    if(y2>z2)
                    {
                        ans1=a;
                        ans2=b;
                        ans3=c;
                    }
                }
                f=1;
            }
        }
    }
    if(!f) cout<<-1;
    else printf("%d %d %d",ans1,ans2,ans3);
    putchar('\n');
    return 0;
}

开了吸氧之后成功搞到了85分(数量可观的分数啊QAQ)

by CSP_Sept @ 2020-03-08 10:43:23

@Hilarious_Reality thx

by Hexarhy @ 2020-03-08 10:45:40

@Herobrine 为什么你们都只有85pts？

明明这种解法可以搞到100pts的

by CSP_Sept @ 2020-03-08 10:45:40

@Hilarious_Reality 艹，A了

by HyyypRtf06 @ 2020-03-08 10:48:48

@Hilarious_Reality 明明是可以跑1e9的好吗qvq（那些O(1)的不要说了