标签:names show 问题 ret int ble const span algo
问题描述:
简单的最小生成树的题,将路径按cost从小到大排序,利用克鲁斯塔尔求最小生成树算法就行。
代码:
1 #include<iostream> 2 #include<queue> 3 #include<algorithm> 4 5 using namespace std; 6 struct Road 7 { 8 int beg; 9 int end; 10 int cost; 11 Road(int beg, int end, int cost) 12 { 13 this->beg = beg; 14 this->end = end; 15 this->cost = cost; 16 } 17 bool operator <(const Road& b) const 18 //必须要带const,使用STL,或者自己写compare函数 19 //优先级大的在队列的前面,所以重载的时候需要注意需要的形式 20 { 21 return (cost > b.cost); 22 } 23 24 }; 25 26 int father[101]; 27 int getfather(int a) //路径压缩 28 { 29 if(father[a] != a) 30 { 31 father[a] = getfather(father[a]); 32 return father[a]; 33 } 34 else 35 return father[a]; 36 } 37 38 priority_queue<Road> q; 39 //并查集 40 41 int num; 42 int vnum; 43 44 int main() 45 { 46 cin>>num>>vnum; 47 int scost = 0; 48 int ok = 0; 49 Road a = {0,0,0}; 50 while(num) 51 { 52 scost = 0; 53 for(int i=0; i<=vnum; i++) 54 { 55 father[i] = i; 56 } 57 for(int i=0; i<num; i++) 58 { 59 cin>>a.beg>>a.end>>a.cost; 60 q.push(a); 61 } 62 while(!q.empty()) 63 { 64 a = q.top(); 65 q.pop(); 66 if(getfather(a.beg) != getfather(a.end)) 67 { 68 father[a.end] = father[a.beg]; 69 scost += a.cost; 70 ok++; 71 } 72 } 73 if(ok == vnum-1) 74 cout<<scost<<endl; 75 else 76 cout<<"?"<<endl; 77 ok = 0; 78 cin>>num>>vnum; 79 80 } 81 return 0; 82 }
标签:names show 问题 ret int ble const span algo
原文地址:https://www.cnblogs.com/Crossea/p/11746940.html