算法实验作业记录(C++)

小明藏书真可谓汗牛充栋，现在有一道难题问：小明到底有多少本不一样的书，每样书的名字是什么，因为有的书名是样的，我们把他视为同样的书。

4
English
Math
Chinese
Chinese

样例输出
3
Chinese 2
English 1
Math 1
代码如下:

//map集合
#include
#include
#include
using namespace std;

int main() {
	int n;
	string name;
	/*char name[101];*/
	map<string,int> books;
	class="superseo">cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> name;
		books[name]++;
	}
	cout << books.size() << endl;
	map<string, int>::iterator it;
	for (it = books.begin(); it != books.end(); it++) {
		cout << it->first << ":\t" << it->second << endl;
	}
	return 0;
}

样例输入
3 2
166 50 30
178 60 23
132 40 15
167 50 30
178 60 23

样例输出
no
yes
代码如下:

//set集合,遍历criminal,man.count()
#include
#include
#include 

using namespace std;

int main() {
	int m, n;
	string people;
	cin >> m >> n;
	set<string> man, criminal;
	getchar();//吸收缓冲区
	for (int i = 0; i < m; i++) {
		getline(cin, people);
		man.insert(people);
	}
	for (int i = 0; i < n; i++) {
		getline(cin, people);
		criminal.insert(people);
	}
	for (auto it = criminal.begin(); it != criminal.end(); ++it) {
		if (man.count(*it) == 1) {
			cout << "yes" << endl;
		}
		else
		{
			cout << "no" << endl;
		}
	}
	return 0;
}

给定n个整数，求里面出现次数最多的数，如果有多个重复出现的数，求值最大的那个。

输入样例1
5
1 1 2 3 4

输出样例1
1 2

//map集合自动排序,小->大,出现次数
#include
#include
using namespace std;
int main() {
	int n;
	map <int, int> num;//默认情况下map根据键的大小采用升序排序
	cin >> n;
	for (int i = 0,x; i < n; ++i) {
		cin >> x;
		num[x]++;
	}
	int max = 0, sum = -1;
	for (map<int,int>::iterator it = num.begin();it != num.end();it++) {
		if (it->second >=sum) {//因为map已经排好序,所以只需要注意数出现的次数
			sum = it->second;
			max = it->first;
		}
	}
	cout << max << "\t" << sum << endl;
	return 0;
}

告诉你每一笔销售记录的水果名称、产地和销售的数量，请生产明细表。

输入样例：
5
apple shandong 3
pineapple guangdong 1
sugarcane guangdong 1
pineapple guangdong 3
pineapple guangdong 1
输出样例
guangdong
|----pineapple(5)
|----sugarcane(1)
shandong
|----apple(3)

//map<产地,map<水果,数量>>
#include
#include
#include
#include 

using namespace std;
int main() {
	int n;
	set<string> poo;//place of origin 
	set<string> fruit;
	map<string,map<string, int>> table;
	cin >> n;
	getchar();
	for (int i = 0, m; i < n; i++) {
		string p, f;
		cin >> f >> p >> m;
		poo.insert(p);
		fruit.insert(f);
		if (!table.count(p)) table[p][f] = 0;	//产地不存在,初始化
		else if (!table[p].count(f)) table[p][f] = 0;//产地的水果不存在,初始化
		table[p][f] += m;//累加
	}
	for (set<string>::iterator it1 = poo.begin(); it1 != poo.end(); ++it1) {
		cout << *it1 << endl;
		for (set<string>::iterator it2 = fruit.begin(); it2 != fruit.end(); ++it2) {
			if (table[*it1].count(*it2)) cout << "  |----" << *it2 << "\t(" << table[*it1][*it2] << ")" << endl;
		}
	}



	return 0;
}

#include
#include
using namespace std;

bool fun(map<int, int> sum, int n) {
	for (map<int, int>::iterator it = sum.begin(); it != sum.end(); it++) {
		if (it->second > n / 2) return true;
	}
	return false;
}

int main() {
	int n;
	map<int, int> sum;
	cin >> n;
	for (int i = 0,m; i < n; i++) {
		cin >> m;
		sum[m]++;
	}
	if (fun(sum, n)) {
		cout << "存在" << endl;
	}
	else {
		cout << "不存在" << endl;
	}
	return 0;
}

//双指针
#include
#include
using namespace std;

string fun(string s) {
	int n = s.length();
	const char* ch = s.c_str();
	int i = 0;
	while (i <= n / 2) {
		if (ch[i] != ch[n - 1 - i]) {
			return "false";
		}
		i++;
	}
	return "true";
}

int main() {
	string a = "abcba", b = "abccba", c = "abcabc";
	cout << "a:" << fun(a) << endl;
	cout << "b:" << fun(b) << endl;
	cout << "c:" << fun(c) << endl;
	return 0;
}

//双指针
#include
#include
#include
using namespace std;

string fun(vector<int> vec,int k) {
	sort(vec.begin(), vec.end());
	for (int i = 0, j = vec.size() - 1; i < j;) {
		int sum = vec[i] + vec[j];
		if (k == sum) {
			cout << vec[i] << " " << vec[j] << endl;
			return "true";
		}
		else if (sum > k) {
			j--;
		}
		else {
			i++;
		}
	}
	return "false";
}

int main() {
	int k = 9;
	vector<int> a{ 6, 1, 4, 2 };
	vector<int> b{ 1,8,3,4,5,10,9 };
	cout <<"a:" << fun(a, k) << endl;
	cout <<"b:" << fun(b, k) << endl;
	return 0;
}

//排序,比较,
#include
#include
using namespace std;

void fun(int *a,int *b,int m,int n) {
	int i = 0, j = 0;
	sort(a, a+m);//先排序
	sort(b, b+n);
	while (i < m && j < n) {
		if (a[i] == b[j]) {
			cout << a[i] << " ";
			i++; j++;
		}
		else if (a[i] > b[j]) {
			j++;
		}
		else {
			i++;
		}
	}
	cout << endl;
}

int main() {
	int a[] {23,32,25,12,34,26,67,54,53,31};
	int b[] {32,53,65,61,13,23,57,76,35,24};
	int m = std::end(a) - std::begin(a);
	int n = std::end(b) - std::begin(b);
	fun(a, b, m, n);
	return 0;
}

#include
#include
using namespace std;
struct MyStruct
{
	int p;	//质因数
	int s;	//次数
};

vector<MyStruct> fun(int n) {
	vector<MyStruct> vec;
	int m = 0;
	MyStruct e;
	for (int i = 2; i <= n; i++) {
		m = 0;
		while(n % i == 0) {
			m++;
			n /= i;
		}
		if (m > 0) {
			e.p = i;
			e.s = m;
			vec.push_back(e);
		}
	}
	return vec;
}

int main() {
	int n = 20;
	vector<MyStruct> res;
	res = fun(n);
	cout << n << endl;
	for (int i = 0; i < res.size(); i++) {
		cout << res[i].p << ":" << res[i].s << endl;
	}
	return 0;
}

20=225

例如{4,1,2,3}相差最小的元素对的个数为3, 元素对为(1,2), (2,3), (3,4).

//排序,直接遍历计算差值,map存储出现次数
#include
#include
#include
#include
using namespace std;


int main() {
	vector<int> vec{ 9,1,5,6,2,3,8 };
	map<int,int> res;
	sort(vec.begin(),vec.end());
	for (vector<int>::iterator it = vec.begin()+1; it != vec.end(); it++) {
		int c = *it - *(it - 1);
		res[c]++;
	}
	cout <<"最小差值:"<< res.begin()->first << " 元素对个数:" << res.begin()->second << endl;
	return 0;
}

#include
#include
#include
using namespace std;

void main(){
	map<string, int> m1;
	map<int, int> m2;
	m1.insert(pair<string, int>("s1", 4));
	m1.insert(pair<string, int>("s2", 3));
	m1.insert(pair<string, int>("s3", 8));
	m1.insert(pair<string, int>("s4", 4));
	m1.insert(pair<string, int>("s5", 3));
	for (map<string, int>::iterator it = m1.begin(); it != m1.end(); it++) {
		m2[it->second]++;
	}
	for (map<int, int>::iterator it = m2.begin(); it != m2.end(); it++) {
		if (it->second > 1) {
			cout << it->first << ":" << it->second << endl;
		}
		
	}
}

#include
#include
#include
using namespace std;

map<int, int> fun(int* a, int* b, int m, int n) {
	int i = 0, j = 0;
	map<int, int> m1;
	while (i < m) {
		m1[a[i]]++;
		i++;
	}
	while (j < n) {
		m1[b[j]]++;
		j++;
	}
	return m1;
}

int main() {
	int a[]{ 23,32,25,12,34,26,67,54,53,31 };
	int b[]{ 32,53,65,61,13,23,57,76,35,24 };
	int m = std::end(a) - std::begin(a);
	int n = std::end(b) - std::begin(b);
	map<int, int> res = fun(a, b, m, n);
	for (map<int, int>::iterator it = res.begin(); it != res.end(); it++) {
		if (it->second > 1) {
			cout << it->first << " " << endl;
		}
	}
	return 0;
}

#include
#include
using namespace std;

int fun(stack<int> &st ,int k) {
	stack<int> st1;
	int a;
	for (int i = 0; i < k; i++) {//出栈到st1
		a = st.top();
		st.pop();
		st1.push(a);
	}
	a = st1.top();//获取第k个元素
	st1.pop();
	while (!st1.empty()) {
		st.push(st1.top());
		st1.pop();
	}
	return a;
}	
//st出栈
void display(stack<int> st) {
	while (!st.empty()) {
		cout << st.top() << " ";
		st.pop();
	}
	cout << endl;
}

int main() {
	stack<int> st;
	st.push(1);
	st.push(2);
	st.push(3);
	st.push(4);
	st.push(5);
	st.push(6);
	st.push(7);
	int k = 3;
	cout << "第" << k << "个元素:" << fun(st, k) << endl;
	display(st);
	return 0;
}