zoukankan      html  css  js  c++  java
  • Educational Codeforces Round 75 (Rated for Div. 2) B. Binary Palindromes

    链接:

    https://codeforces.com/contest/1251/problem/B

    题意:

    A palindrome is a string t which reads the same backward as forward (formally, t[i]=t[|t|+1−i] for all i∈[1,|t|]). Here |t| denotes the length of a string t. For example, the strings 010, 1001 and 0 are palindromes.

    You have n binary strings s1,s2,…,sn (each si consists of zeroes and/or ones). You can swap any pair of characters any number of times (possibly, zero). Characters can be either from the same string or from different strings — there are no restrictions.

    Formally, in one move you:

    choose four integer numbers x,a,y,b such that 1≤x,y≤n and 1≤a≤|sx| and 1≤b≤|sy| (where x and y are string indices and a and b are positions in strings sx and sy respectively),
    swap (exchange) the characters sx[a] and sy[b].
    What is the maximum number of strings you can make palindromic simultaneously?

    思路:

    考虑所有串的长度,当有奇数长度存在时,保证可以交换出全部,当没有时, 可能存在0或1为奇数,不能配对,有奇数可以将奇数减位,同时保证剩下的偶数相等。

    代码:

    #include<bits/stdc++.h>
    using namespace std;
    typedef long long LL;
    
    int n;
    string s;
    
    int main()
    {
        int t;
        scanf("%d", &t);
        while(t--)
        {
            int one = 0, zer = 0;
            int q = 0;
            scanf("%d", &n);
            for (int i = 1;i <= n;i++)
            {
                cin >> s;
                int len = (int)s.length();
                if (len%2)
                    q++;
                for (int j = 0;j < len;j++)
                {
                    if (s[j] == '0')
                        zer++;
                    else
                        one++;
                }
            }
            if (q > 0)
                printf("%d
    ", n);
            else
            {
                if (one%2 || zer%2)
                    printf("%d
    ", n-1);
                else
                    printf("%d
    ", n);
            }
        }
        return 0;
    }
    
  • 相关阅读:
    犀牛书学习笔记(2):对象和数组
    犀牛书学习笔记(1):语法结构、数据类型和值、表达式和运算符
    小学了一下css hack
    git学习系列--六分之一
    稍览了一下CommonJS
    意识流_六分之一
    两升的心思系列之-----粒子的预备
    mybatis_延迟加载
    mybatis_动态SQL
    mybatis_mapper动态代理
  • 原文地址:https://www.cnblogs.com/YDDDD/p/11779066.html
Copyright © 2011-2022 走看看