优化finding函数,#include<algorithm> #include<iostream> #include<vector> #include<string> #include<cmath> #include <cstdio> #include <map> #include <unordered_map> #include <queue> using namespace std; const int INF = 0x3f3f3f3f; int n, gamma, time_count=0; int time[10]; string alpha; vector<int> Length(50005, 0); unordered_map<string, int> number; unordered_map<int, string> nega_number; vector<unordered_map<int, int>> edge(50005); vector<int> trace(50005, 0); vector<int> final_trace; void finding(string alpha) { int a=number[alpha], b; char beta; string epsilon; for(int i=9; i>=0; i--) { for(int j=1; j<10; j++) { epsilon = alpha; epsilon[i] = '0' + (int(epsilon[i]) + j) % 10; if(number.find(epsilon) != number.end() and epsilon != alpha) { b = number[epsilon]; edge[a][b]= time[i]; } } for(int j=i-1; j>=0; j--) { epsilon = alpha; beta = epsilon[j]; epsilon[j] = epsilon[i]; epsilon[i] = beta; if(number.find(epsilon) != number.end() and epsilon != alpha) { b = number[epsilon]; edge[a][b]= time[j]; } } } } void dijkstra(int i) { priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q; vector<bool> vis(n+1, false); q.push({0, i}); Length[i] = 0; while(!q.empty()) { int u = q.top().second; q.pop(); if(vis[u]) continue; vis[u] = true; for(auto j : edge[u]) { int v = j.first, w = j.second; if(Length[v] > Length[u] + w) { Length[v] = Length[u] + w; trace[v] = u; q.push({Length[v], v}); } } } } int main() { cin>>n; for(int i=2; i<n+1;i++) { Length[i] = INF; } for(int i=0; i<10; i++) { cin>>time[i]; } for(int i=0; i<n; i++) { cin>>alpha; nega_number[i] = alpha; number[alpha] = i+1; } for(int i=0; i<n; i++) { alpha = nega_number[i]; finding(alpha); } dijkstra(1); if(Length[n] == INF) { cout<<"-1"; } else { gamma = n; final_trace.push_back(gamma); cout<<Length[n]<<endl; while(gamma != 1) { gamma = trace[gamma]; final_trace.push_back(gamma); } cout<<final_trace.size()<<endl; for(int i=final_trace.size()-1;i>-1;i--) { cout<<final_trace[i]<<" "; } } system("pause"); return 0; }
时间: 2024-01-13 15:04:48 浏览: 106
可以对finding函数进行以下优化:
1. 将string类型的alpha改为int类型的a,避免在函数中多次进行string和int类型的转换。
2. 将时间复杂度较高的除法运算改为直接进行取余运算。
优化后的代码如下:
```c++
void finding(int a) {
int b;
string epsilon;
for (int i = 9; i >= 0; i--) {
for (int j = 1; j < 10; j++) {
epsilon = to_string(a);
epsilon[i] = '0' + (epsilon[i] - '0' + j) % 10;
if (number.find(epsilon) != number.end() && epsilon != to_string(a)) {
b = number[epsilon];
edge[a][b] = time[i];
}
}
for (int j = i - 1; j >= 0; j--) {
epsilon = to_string(a);
char beta = epsilon[j];
epsilon[j] = epsilon[i];
epsilon[i] = beta;
if (number.find(epsilon) != number.end() && epsilon != to_string(a)) {
b = number[epsilon];
edge[a][b] = time[j];
}
}
}
}
```
另外,建议将system("pause")移除,因为它只在Windows系统上有效,在其他系统上可能会出现问题。可以使用cin.get()或者getchar()代替。
阅读全文
相关推荐
![-](https://img-home.csdnimg.cn/images/20241231044930.png)
![-](https://img-home.csdnimg.cn/images/20241231044930.png)
![-](https://img-home.csdnimg.cn/images/20250102104920.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![rar](https://img-home.csdnimg.cn/images/20241231044955.png)
![7z](https://img-home.csdnimg.cn/images/20241231044736.png)
![application/pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20241231044930.png)
![pdf](https://img-home.csdnimg.cn/images/20241231044930.png)
![zip](https://img-home.csdnimg.cn/images/20241231045053.png)
![pdf](https://img-home.csdnimg.cn/images/20241231044930.png)
![pdf](https://img-home.csdnimg.cn/images/20241231044930.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)