CodeForces 353B Two Heaps

本文探讨如何通过策略最大化生成不同四数整数的数量,涉及整数分组与组合的数学逻辑。
B. Two Heaps
 

Valera has n cubes, each cube contains an integer from 10 to 99. He arbitrarily chooses n cubes and puts them in the first heap. The remaining cubes form the second heap.

Valera decided to play with cubes. During the game he takes a cube from the first heap and writes down the number it has. Then he takes a cube from the second heap and write out its two digits near two digits he had written (to the right of them). In the end he obtained a single fourdigit integer — the first two digits of it is written on the cube from the first heap, and the second two digits of it is written on the second cube from the second heap.

Valera knows arithmetic very well. So, he can easily count the number of distinct fourdigit numbers he can get in the game. The other question is: how to split cubes into two heaps so that this number (the number of distinct fourdigit integers Valera can get) will be as large as possible?

Input

The first line contains integer n (1 ≤ n ≤ 100). The second line contains n space-separated integers ai (10 ≤ ai ≤ 99), denoting the numbers on the cubes.

Output

In the first line print a single number — the maximum possible number of distinct four-digit numbers Valera can obtain. In the second line print n numbers bi (1 ≤ bi ≤ 2). The numbers mean: the i-th cube belongs to the bi-th heap in your division.

If there are multiple optimal ways to split the cubes into the heaps, print any of them.

Sample test(s)
input
1
10 99
output
1
2 1
input
2
13 24 13 45
output
4
1 2 2 1
Note

In the first test case Valera can put the first cube in the first heap, and second cube — in second heap. In this case he obtain number1099. If he put the second cube in the first heap, and the first cube in the second heap, then he can obtain number 9910. In both cases the maximum number of distinct integers is equal to one.

In the second test case Valera can obtain numbers 1313, 1345, 2413, 2445. Note, that if he put the first and the third cubes in the first heap, he can obtain only two numbers 1324 and 1345.

 重复出现2次及以上的数,先在两边各分一个。。。只出现一次的数分成尽量相等的两半。。。。
用剩下的出现2次及以上的数把两个堆补齐。。。。。

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 
 5 using namespace std;
 6 
 7 int n,use[100],a[220],cnt[100],cnt1=0,cnt2=0,temp=0,sol[220],size1=0;
 8 
 9 int main()
10 {
11     scanf("%d",&n);
12     n=n*2;
13     for(int i=0;i<n;i++)
14     {
15         scanf("%d",a+i);
16         cnt[a[i]]++;
17     }
18     for(int i=10;i<=99;i++)
19     {
20         if(cnt[i]>=2) cnt2++;
21         else if(cnt[i]==1) cnt1++;
22     }
23     int ans=(cnt2+(cnt1/2))*(cnt2+((cnt1+1)/2));
24     for(int i=0;i<n;i++)
25     {
26         if(cnt[a[i]]>=2&&use[a[i]]<2)
27         {
28             sol[i]=++use[a[i]];
29             if(sol[i]==1) size1++;
30         }
31         else if(cnt[a[i]]==1)
32         {
33             if(temp<cnt1/2)
34             {
35                 sol[i]=1;
36                 size1++;
37                 temp++;
38             }
39             else sol[i]=2;
40         }
41     }
42     printf("%d\n",ans);
43     for(int i=0;i<n;i++)
44     {
45         if(sol[i]) printf("%d ",sol[i]);
46         else
47         {
48             if(size1<n/2) {printf("1 "); size1++;}
49             else printf("2 ");
50         }
51     }
52     return 0;
53 }

 

 

### 关于 Codeforces 1853B 的题解与实现 尽管当前未提供关于 Codeforces 1853B 的具体引用内容,但可以根据常见的竞赛编程问题模式以及相关算法知识来推测可能的解决方案。 #### 题目概述 通常情况下,Codeforces B 类题目涉及基础数据结构或简单算法的应用。假设该题目要求处理某种数组操作或者字符串匹配,则可以采用如下方法解决: #### 解决方案分析 如果题目涉及到数组查询或修改操作,一种常见的方式是利用前缀和技巧优化时间复杂度[^3]。例如,对于区间求和问题,可以通过预计算前缀和数组快速得到任意区间的总和。 以下是基于上述假设的一个 Python 实现示例: ```python def solve_1853B(): import sys input = sys.stdin.read data = input().split() n, q = map(int, data[0].split()) # 数组长度和询问次数 array = list(map(int, data[1].split())) # 初始数组 prefix_sum = [0] * (n + 1) for i in range(1, n + 1): prefix_sum[i] = prefix_sum[i - 1] + array[i - 1] results = [] for _ in range(q): l, r = map(int, data[2:].pop(0).split()) current_sum = prefix_sum[r] - prefix_sum[l - 1] results.append(current_sum % (10**9 + 7)) return results print(*solve_1853B(), sep='\n') ``` 此代码片段展示了如何通过构建 `prefix_sum` 来高效响应多次区间求和请求,并对结果取模 \(10^9+7\) 输出[^4]。 #### 进一步扩展思考 当面对更复杂的约束条件时,动态规划或其他高级技术可能会被引入到解答之中。然而,在没有确切了解本题细节之前,以上仅作为通用策略分享给用户参考。
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