洛谷P2504聪明的猴子
思路：最小生成树
1 #include<cstdio> 2 #include<cstdlib> 3 #include<iostream> 4 #include<cstring> 5 #include<cmath> 6 #include<algorithm> 7 #include<vector> 8 using namespace std; 9 int n, m; 10 int countx = 0, res[1005];//记录加入的边数,边 11 int nodex[1005][2]; 12 //并查集 13 int f[500505] = { 0 }; 14 int find(int x) { return f[x] == x ? x : f[x] = find(f[x]); } 15 void merge(int x, int y) { f[find(x)] = find(y); }//x根连在y的根上 16 void kruskal(vector<vector< int>> x) { 17 for (int i = 1; i < m + 1; i++) { 18 if (find(x[i][1]) != find(x[i][2])) {//判断是否该边两节点已连通 19 merge(x[i][1], x[i][2]);//连通 20 countx++; 21 res[countx] = x[i][0]; 22 } 23 if (countx == n - 1) break;//全部连通 24 } 25 } 26 int lengthx(int x1, int y1, int x2, int y2) { 27 return (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2); 28 } 29 int main() 30 { 31 int monkey_num = 0, monkey[505]; 32 scanf("%d", &monkey_num); 33 for (int i = 1; i <= monkey_num; i++) scanf("%d", &monkey[i]); 34 sort(monkey + 1, monkey + monkey_num + 1); 35 scanf("%d", &n); 36 for (int i = 1; i <= n; i++) scanf("%d %d", &nodex[i][0],&nodex[i][1]); 37 m = 0; 38 for (int i = 1; i < n; i++) m += i; 39 for (int i = 1; i < m + 1; i++) f[i] = i; //初始化并查集 40 vector<vector< int>> edge(m + 1, vector<int>(3, 0)); 41 int c = 0; 42 for (int i = 1; i < n; i++) { 43 for (int j = i + 1; j <= n; j++) { 44 edge[++c][1] = i; 45 edge[c][2] = j; 46 edge[c][0] = lengthx(nodex[i][0], nodex[i][1], nodex[j][0], nodex[j][1]); 47 } 48 } 49 sort(edge.begin(), edge.end());//按边权值升序排列 50 kruskal(edge); 51 int maxres = 0; 52 for (int i = 1; i < n; i++) maxres = max(res[i], maxres); 53 int ress = 1; 54 while (maxres > monkey[ress] * monkey[ress] && ress <= monkey_num) ress++; 55 printf("%d", monkey_num - ress + 1); 56 return 0; 57 }
