hihoCoder#1097 最小生成树一·Prim算法

 1 #include <iostream>
 2 #include <cstring>
 3 
 4 using namespace std;
 5 
 6 #define MAX_POINT 1024
 7 
 8 int N;
 9 int g[MAX_POINT][MAX_POINT];
10 bool visited[MAX_POINT];
11 
12 int prime() {
13   int res = 0;
14   int left = N - 1;
15   visited[1] = true;
16   while (left) {
17     int k = 0;
18     for (int i = 1; i <= N; i++)
19       if (!visited[i] && g[1][i] < g[1][k])
20         k = i;
21     visited[k] = true;
22     left--;
23     res += g[1][k];
24     g[1][k] = g[k][1] = 0;
25     for (int i = 1; i <= N; i++)
26       if (!visited[i] && g[1][i] > g[1][k] + g[k][i])
27         g[1][i] = g[i][1] = g[1][k] + g[k][i];
28   }
29 
30   return res;
31 }
32 
33 int main() {
34   memset(g, 1, sizeof(g));
35   memset(visited, false, sizeof(visited));
36   scanf("%d", &N);
37   for (int i = 1; i <= N; i++)
38     for (int j = 1; j <= N; j++)
39       scanf("%d", &(g[i][j]));
40   printf("%d\n", prime());
41 
42   return 0;
43 }