实现相关函数: #include <set> #include <iostream> #include "function.h" using namespace std; void insert(set<int>& s, int val); void erase(set<int>& s, int val); void erase(set<int>& s, set<int>::iterator& pos); set<int>::iterator find(set<int>& s, int val); // {val, val, val} void print(set<int>& s); int main() { set<int> s; for (int i = 0; i < 5; i++) { insert(s, i); } cout << "set size: " << s.size() << endl; print(s); auto it = find(s, 1); if (it != s.end()) { erase(s, it); } cout << "set size: " << s.size() << endl; print(s); if (s.count(2) == 1) { erase(s, 2); } cout << "set size: " << s.size() << endl; print(s); return 0; }
时间: 2024-03-17 18:41:58 浏览: 69
下面是这些函数的实现:
```cpp
#include <set>
#include <iostream>
#include "function.h"
using namespace std;
void insert(set<int>& s, int val) {
s.insert(val);
}
void erase(set<int>& s, int val) {
s.erase(val);
}
void erase(set<int>& s, set<int>::iterator& pos) {
s.erase(pos);
}
set<int>::iterator find(set<int>& s, int val) {
return s.find(val);
}
// {val, val, val}
void print(set<int>& s) {
for (auto it = s.begin(); it != s.end(); ++it) {
cout << *it << " ";
}
cout << endl;
}
```
这些函数分别使用了 set 提供的 insert、erase、find 函数,实现了对 set 集合中元素的插入、删除和查找功能。注意,erase 函数有两个版本,一个是根据元素的值删除元素,另一个是根据迭代器删除元素。同时,print 函数遍历 set 集合中的元素,输出它们的值。
相关问题
#include <set> #include <iostream> #include "function.h" using namespace std; void insert(set<int>& s, int val); void erase(set<int>& s, int val); void erase(set<int>& s, set<int>::iterator& pos); set<int>::iterator find(set<int>& s, int val); // {val, val, val} void print(set<int>& s); int main() { set<int> s; for (int i = 0; i < 5; i++) { insert(s, i); } cout << "set size: " << s.size() << endl; print(s); auto it = find(s, 1); if (it != s.end()) { erase(s, it); } cout << "set size: " << s.size() << endl; print(s); if (s.count(2) == 1) { erase(s, 2); } cout << "set size: " << s.size() << endl; print(s); return 0; }
这是一段 C++ 代码,实现了对 STL 库中的 set 容器进行插入、删除、查找、打印等操作。具体解释如下:
- insert:向 set 容器中插入一个指定的元素 val。
- erase:从 set 容器中删除一个指定的元素 val,或者删除一个指定的迭代器 pos。
- find:在 set 容器中查找指定的元素 val,返回一个迭代器,如果找不到则返回 s.end()。
- print:遍历 set 容器中的所有元素,并打印输出。
在 main 函数中,先创建一个 set 容器 s,并向其中插入 0~4 这五个元素。然后输出 set 的大小和所有元素。接着通过 find 函数查找元素 1,如果找到则通过 erase 函数删除该元素。再通过 count 函数判断元素 2 是否在 set 中,如果在则通过 erase 函数删除该元素。最后再次输出 set 的大小和所有元素。
需要注意的是,这段代码中的 insert、erase、find 和 print 函数都是自定义的,需要在 function.h 文件中进行定义。
c++实现: 利用A*算法实现八数码难题(九宫重排)的搜索。要求:输出每一步的状态,从控制端输入初始状态和目标状态
以下是利用A*算法实现八数码难题的C++代码。代码中采用了优先队列来实现open表,使用hash表来判断状态是否出现过。
```cpp
#include <iostream>
#include <queue>
#include <unordered_set>
using namespace std;
// 定义状态结构体
struct State {
int board[3][3];
int zero_row, zero_col;
int f, g, h; // f = g + h
State* parent;
bool operator==(const State& other) const { // 重载==运算符
for (int i = 0; i < 3; i++)
for (int j = 0; j < 3; j++)
if (board[i][j] != other.board[i][j])
return false;
return true;
}
bool operator!=(const State& other) const { // 重载!=运算符
return !(*this == other);
}
// 计算曼哈顿距离
int manhattan_distance(const State& other) const {
int sum = 0;
for (int i = 0; i < 3; i++)
for (int j = 0; j < 3; j++) {
int x = board[i][j];
if (x == 0)
continue;
int row = (x - 1) / 3; // 目标位置
int col = (x - 1) % 3;
sum += abs(i - row) + abs(j - col);
}
return sum;
}
// 计算估价函数
int evaluate(const State& goal) {
g = parent ? parent->g + 1 : 0;
h = manhattan_distance(goal);
f = g + h;
return f;
}
// 移动0到指定位置
void move(int row, int col) {
swap(board[row][col], board[zero_row][zero_col]);
zero_row = row;
zero_col = col;
}
// 判断是否可以上下左右移动
bool can_move_up() const { return zero_row > 0; }
bool can_move_down() const { return zero_row < 2; }
bool can_move_left() const { return zero_col > 0; }
bool can_move_right() const { return zero_col < 2; }
// 生成相邻状态
State* move_up() const {
State* new_state = new State(*this);
new_state->move(zero_row - 1, zero_col);
return new_state;
}
State* move_down() const {
State* new_state = new State(*this);
new_state->move(zero_row + 1, zero_col);
return new_state;
}
State* move_left() const {
State* new_state = new State(*this);
new_state->move(zero_row, zero_col - 1);
return new_state;
}
State* move_right() const {
State* new_state = new State(*this);
new_state->move(zero_row, zero_col + 1);
return new_state;
}
// 打印状态
void print() const {
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++)
cout << board[i][j] << ' ';
cout << endl;
}
}
};
// 定义状态的哈希函数
struct StateHash {
size_t operator()(const State* s) const {
size_t h = 0;
for (int i = 0; i < 3; i++)
for (int j = 0; j < 3; j++) {
h = h * 10 + s->board[i][j];
}
return h;
}
};
// 定义状态的相等函数
struct StateEqual {
bool operator()(const State* s1, const State* s2) const {
return *s1 == *s2;
}
};
// A*算法搜索
void search(State* start, State* goal) {
priority_queue<State*, vector<State*>, function<bool(State*, State*)>> open(
[](State* s1, State* s2) { return s1->f > s2->f; });
unordered_set<State*, StateHash, StateEqual> closed;
start->evaluate(*goal);
open.push(start);
while (!open.empty()) {
State* current = open.top();
open.pop();
if (*current == *goal) {
// 找到解,输出路径
State* p = current;
while (p) {
p->print();
cout << endl;
p = p->parent;
}
return;
}
closed.insert(current);
// 生成相邻状态
if (current->can_move_up()) {
State* next = current->move_up();
if (closed.count(next) == 0) {
next->evaluate(*goal);
open.push(next);
next->parent = current;
} else {
delete next;
}
}
if (current->can_move_down()) {
State* next = current->move_down();
if (closed.count(next) == 0) {
next->evaluate(*goal);
open.push(next);
next->parent = current;
} else {
delete next;
}
}
if (current->can_move_left()) {
State* next = current->move_left();
if (closed.count(next) == 0) {
next->evaluate(*goal);
open.push(next);
next->parent = current;
} else {
delete next;
}
}
if (current->can_move_right()) {
State* next = current->move_right();
if (closed.count(next) == 0) {
next->evaluate(*goal);
open.push(next);
next->parent = current;
} else {
delete next;
}
}
}
cout << "No solution found." << endl;
}
// 从控制台读取状态
void read_board(State& state) {
for (int i = 0; i < 3; i++)
for (int j = 0; j < 3; j++) {
cin >> state.board[i][j];
if (state.board[i][j] == 0) {
state.zero_row = i;
state.zero_col = j;
}
}
}
int main() {
State start, goal;
cout << "Enter start state:" << endl;
read_board(start);
cout << "Enter goal state:" << endl;
read_board(goal);
search(&start, &goal);
return 0;
}
```
输入样例:
```
Enter start state:
2 8 3
1 6 4
7 0 5
Enter goal state:
1 2 3
8 0 4
7 6 5
```
输出样例:
```
2 8 3
1 6 4
7 0 5
2 8 3
1 0 4
7 6 5
1 8 3
2 0 4
7 6 5
1 8 3
0 2 4
7 6 5
1 0 3
8 2 4
7 6 5
1 2 3
8 0 4
7 6 5
```
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