哈希散列

問題 A: 誰是你的潛在朋友

#include <iostream>
using namespace std;
int main()
{
	int n, m;
	while (cin >> n >> m)
	{
		int a[205], h[205] = { 0 };
		for (int i = 0; i < n; i++)
		{
			cin >> a[i];
			h[a[i]]++;
		}
		
		for (int i = 0; i < n; i++)
		{
			if (h[a[i]] > 1)
			{
				cout << a[i] - 1 << endl;;
			}
			else
			{
				cout << "BeiJu" << endl;
			}
		}
	}
	return 0;
} 

問題 B: 分組統計

#include <iostream>
#include <set>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
int main()
{
	int n, m, max;
	cin >> m;
	while (m--)
	{
		cin >> n;
		vector<int> v[1005];
		set<int> s;
		int a[1005], b[1005];
		for (int i = 0; i < 1005; i++)
		{
			v[i].clear();
		}
		for (int i = 0; i < n; i++)
		{
			cin >> a[i];
			s.insert(a[i]);
		}
		for (int i = 0; i < n; i++)
		{
			int x;
			cin >> x;
			v[x].push_back(a[i]);
		}
		for (int i = 0; i < 105; i++)
		{
			if (v[i].size())
			{
				memset(b, 0, sizeof(b));
				for (int j = 0; j < v[i].size(); j++)
				{
					b[v[i][j]]++;
				}
				cout << i << "=" << "{";
				int flag = 0;
				int k = 1;
				for (auto j = s.begin(); j != s.end(); j++)
				{
					if (flag == 0)
					{
						cout << *j << "=" << b[*j];
						flag = 1;
					}
					else
					{
						cout << "," << *j << "=" << b[*j];
					}
				}
				cout << "}" << endl;
			}
		}
	}
	return 0;
}

問題 C: Be Unique

#include<iostream>
#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
	int n;
	while(cin >> n)
	{
		
		int a[10005] = { 0 };
		int bets[10005] = { 0 };
		for(int i = 0; i < n; i++)
		{
			cin >> a[i];
			bets[a[i]]++;
		}
		int ans = -1;
		for(int i = 0; i < n; i++)
		{
			if(bets[a[i]] == 1)
			{ 
				ans = a[i];
				break;
			} 
		}	
		if(ans == -1)
		{
			cout << "None" << endl;
		}
		else
		{
			cout << ans << endl;
		}
	}
}

問題 D: String Subtraction

#include <iostream>
#include <string>
using namespace std;
int main()
{
	string s1, s2;
	getline(cin, s1);
	getline(cin, s2);
	for (int i = 0; i < s1.length(); i++)
	{
		if (s2.find(s1[i]) == string::npos)
		{
			cout << s1[i];
		} 
	}
	return 0;
}