50分。。。有些ac有些wa有些tle。。。求助各位大佬，谢谢

吠悟 @ 2020-02-09 11:59:19

#include<iostream>
#include<cmath>
using namespace std;
bool isprime(int x)
{
    int s = sqrt(double(x));
    for (int i = 2;i <= s;i++)
    {
        if (x % i == 0)
            return false;
    }
    return true;
}
int main()
{
    int n,count=0;
    cin >> n;
    int a[10000];
    int min=99999, minx=0,miny=0,minz=0;
    for (int i = 2; i <= n;i++)
    {
        if (isprime(i))
        {
            a[count] = i;
            count++;
        }
    }
    for (int i = 0;i <= count;i++)
    {
        for (int j = i;j <= count;j++)
        {
            for (int k = j;k <= count;k++)
            {
                if (a[i] + a[j] + a[k] == n)
                {
                    if (a[i] < min)
                    {
                        min = a[i];
                        minx = a[i];
                        miny = a[j];
                        minz = a[k];
                    }
                }
            }
        }
    }
    cout << minx << " " << miny << " " << minz;
}

by zhanghzqwq @ 2020-02-09 12:01:09

求质数没判断0和1

by ztxtjz @ 2020-02-09 12:03:03

只需要两次循环，每一次循环后就判一下质数，再判一下n减去这两个数是不是质数

by zhanghzqwq @ 2020-02-09 12:03:49

@吠悟 0和1不是质数

by 吠悟 @ 2020-02-09 12:06:13

@zhanghanzhang 不需要啊。。。我程序里是把小于等于n的质数全都储存到数组里面，这样就不用考虑0和1了吧

by Dimly_dust @ 2020-02-09 12:06:41

@吠悟

#include <bits/stdc++.h>
int num,Prime[100001],n;
bool notPrime[100001];
void init()
{
    notPrime[1]=1;
    for(int i=2; i<=n; ++i)
    {
        if(!notPrime[i])
            Prime[++num]=i;
        for(int j=1; j<=num&&i*Prime[j]<=n; ++j)
        {
            notPrime[i*Prime[j]]=1;
            if(i%Prime[j]==0) break;
        }
    }
}
int main()
{
    cin>>n;
    init();
    for(int i=1; i<=num; ++i)
    {
        for(int j=i; j<=num; ++j)
        {
            if(!notPrime[n-Prime[i]-Prime[j]]&&n-Prime[i]-Prime[j]>0)
            {
                cout<<Prime[i]<<Prime[j]<<n-Prime[i]-Prime[j];
                return 0;
            }
        }
    }
    return 0;
}

你再试试

by 吠悟 @ 2020-02-09 12:07:57

@缥缈于尘 洛谷说编译失败。。。

by zhanghzqwq @ 2020-02-09 12:09:06

#include<iostream>
using namespace std;
bool isPrime(int n){
    for(int i=2;i*i<=n;i++){
        if(n%i==0){
            return false;
        }
    }
    return true;
}
int main(){
    int n;
    cin>>n;
    for(int i=2;i<n;i++){
        for(int j=2;j<n;j++){
            if(isPrime(i)&&isPrime(j)&&isPrime(n-i-j)&&n-i-j>=2){
                cout<<i<<" "<<j<<" "<<n-i-j<<endl;
                return 0;
            }
        }
    }
    return 0;
}

开两层循环

by Dimly_dust @ 2020-02-09 12:10:04

@吠悟

在
#include <bits/stdc++.h>
后换行加
using namespace std;

by Dimly_dust @ 2020-02-09 12:10:24

抱歉

by 吠悟 @ 2020-02-09 12:11:28

@zhanghanzhang 谢谢大佬