Codeforces Round #556 (Div. 2) C. Prefix Sum Primes

题目大意让你改变数组的排序,使前缀和的素数最多;

这是一道模拟题,让你通过判断1和2的个数来解决,

只要特判一下1的个数是零的时候,2的个数是零的时候,或者1只有一个而2的个数又不是0个的时候,剩下的情况我们只有把1的个数分奇数和偶数来考虑,大致思路是这样,接下来就看代码吧

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn = 200010;
int main()
{
    int a[maxn];
    int n;
    cin >> n;
    int ans1 = 0, ans2 = 0;
    for (int i = 0; i < n; i++)
    {
        scanf("%d", &a[i]);
        if (a[i] == 1)ans1++;
        else ans2++;
    }

     if (ans1 == 1 && ans2 !=0)
    {
        printf("2 1");
        for (int i = 1;i < ans2;i++)printf(" 2");
    }
    else if (ans1 == 0 && ans2 != 0)
    {
        for (int i = 0;i < ans2;i++)printf("2 ");
    }
    else if (ans2 == 0 && ans1 != 0)
    {
        for (int i = 0;i < ans1;i++)printf("1 ");
    }
    else
     {
         printf("2 1");
         if (ans1 % 2 == 1)
         {
             for (int i = 1;i < ans1;i++)printf(" 1");
             for (int i = 1;i < ans2;i++)printf(" 2");
         }
         else
         {
             for (int i = 1;i < ans1-1;i++)printf(" 1");
             for (int i = 1;i < ans2;i++)printf(" 2");
             printf(" 1");
         }
     }
}

原文地址:https://www.cnblogs.com/csxaxx/p/10801378.html

时间: 2024-10-08 03:07:11

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