Vika and her friends went shopping in a mall, which can be represented as a rectangular grid of rooms with sides of length n and m. Each room has coordinates (a, b), where 1 ≤ a ≤ n, 1 ≤ b ≤ m. Thus we call a hall with coordinates (c, d) a neighbouring for it if |a-c|+|b-d|=1.Tired of empty fashion talks, Vika decided to sneak away unnoticed. But since she hasn't had a chance to visit one of the shops yet, she doesn't want to leave the mall. After a while, her friends noticed Vika's disappearance and started looking for her.Currently, Vika is in a room with coordinates (z, y), and her k friends are in rooms with coordinates (x1, Y1), (x2, 32),..,(ük) 3k).respectively. The coordinates can coincide. Note that all the girls must move to the neighbouring rooms.Every minute, first Vika moves to one of the adjacent to the side rooms of her choice, and then each friend (seeing Vika's choice) also chooses one of the adjacent rooms to move to.If at the end of the minute (that is, after all the girls have moved on to the neighbouring rooms) at least one friend is in the same room as Vika, she is caught and all the other friends are called.Tell us, can Vika run away from her annoying friends forever, or will she have to continue listening to empty fashion talks after some time?如果能不被抓住输出yes,否则输出no,给出c++代码及中文解释
时间: 2024-02-14 15:32:27 浏览: 124
可以使用深度优先搜索(DFS)来解决这个问题。首先,我们可以将问题抽象为一个图,其中每个房间都是一个节点,相邻房间之间有边相连。
首先,我们需要定义一个辅助函数,用于检查给定的坐标是否在合法的范围内:
```cpp
bool isValid(int x, int y, int n, int m) {
return (x >= 1 && x <= n && y >= 1 && y <= m);
}
```
接下来,我们可以使用DFS来遍历所有可能的移动方式。我们从Vika的起始位置开始,依次向四个方向移动,然后递归地对每个朋友进行相同的操作。如果在递归过程中,任何一个朋友与Vika在同一个房间,则说明Vika会被抓住。
以下是完整的C++代码实现:
```cpp
#include <iostream>
#include <vector>
using namespace std;
bool isValid(int x, int y, int n, int m) {
return (x >= 1 && x <= n && y >= 1 && y <= m);
}
bool dfs(int vx, int vy, vector<pair<int, int>>& friends, vector<vector<bool>>& visited, int n, int m) {
if (vx == 0 && vy == 0) {
// Vika has successfully escaped
return true;
}
visited[vx][vy] = true;
// Possible neighbors' coordinates
vector<pair<int, int>> neighbors = {{vx-1, vy}, {vx+1, vy}, {vx, vy-1}, {vx, vy+1}};
for (auto neighbor : neighbors) {
int nx = neighbor.first;
int ny = neighbor.second;
if (isValid(nx, ny, n, m) && !visited[nx][ny]) {
bool caught = false;
for (auto friendCoord : friends) {
int fx = friendCoord.first;
int fy = friendCoord.second;
if (nx == fx && ny == fy) {
caught = true;
break;
}
}
if (!caught && dfs(nx, ny, friends, visited, n, m)) {
return true;
}
}
}
return false;
}
string canVikaEscape(int n, int m, int vx, int vy, vector<pair<int, int>>& friends) {
vector<vector<bool>> visited(n+1, vector<bool>(m+1, false));
if (dfs(vx, vy, friends, visited, n, m)) {
return "Yes";
} else {
return "No";
}
}
int main() {
int n, m, vx, vy, k;
cin >> n >> m >> vx >> vy >> k;
vector<pair<int, int>> friends(k);
for (int i = 0; i < k; i++) {
cin >> friends[i].first >> friends[i].second;
}
cout << canVikaEscape(n, m, vx, vy, friends) << endl;
return 0;
}
```
该代码首先读取输入的n,m,vx,vy和k值。接下来,它读取k个朋友的坐标,并调用canVikaEscape函数来判断Vika是否能逃脱。最后,它输出结果。
希望这可以帮助到你!
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