2021-08-12

Posted 2021-09-05 李憨憨_

练习一

组队竞赛：
题目描述

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
    int n;
    while(cin >> n)
    {
        vector<int> a;
        a.resize(3 * n);
        for(int i = 0; i < (3 * n); ++i)
        {
            cin >> a[i];
        }
        sort(a.begin(), a.end());
        long long sum = 0;
        for(int i = 0; i < n; ++i)
        {
            sum += a[(a.size() - (2 * (i + 1)))];
        }
        cout << sum << endl;
    }
    return 0;
}

练习二

OR63.删除公共字符

#include <iostream>
#include <string>
using namespace std;

int main()
{
    string str1, str2;
    getline(cin, str1);
    getline(cin, str2);
    int hash[256] = {0};
    for(int i = 0; i < str2.size(); ++i)
    {
        hash[str2[i]]++;
    }
    string ret = "";
    for(int j = 0; j < str1.size(); ++j)
    {
        if(hash[str1[j]] == 0)
            ret += str1[j];
    }
    cout << ret << endl;
    return 0;
}

练习三

排序子序列
题目描述：

#include <iostream>
#include <vector>
using namespace std;
int main()
{
	int n;
	cin >> n;
	vector<int> a;
	a.resize(n + 1)
	a[n] = 0;
	int i = 0;
	for (i = 0; i < n; ++i)
		cin >> a[i];
	i = 0;
	int count = 0;
	while (i < n)
	{
		if (a[i] < a[i + 1])
		{
			while (i < n && a[i] <= a[i + 1])
				i++;
			count++;
			i++;
		} 
    	else if (a[i] == a[i + 1])
		{
			i++;
		} 
		else 
		{
			while (i < n && a[i] >= a[i + 1])
				i++;
			count++;
			i++;
		}
	} 
	cout << count << endl;
	return 0;
}