最小生成树之rst

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <cstring>
#include <time.h>
using namespace std;


#define MAXN 1000
#define INF 0x3f3f3f3f
#define NOT_USED 0
#define USED 1


int n, cnt; // n:点个数 cnt:边条数
int g[MAXN][MAXN];
int ans[MAXN][MAXN];
int node[MAXN];
int weight;


void init(){
memset(g   , 0       , sizeof(g)    );
memset(ans , 0       , sizeof(ans)  );
memset(node, NOT_USED, sizeof(node) );
weight = 0;
}


int get_rand(int left, int right){
return left + rand() % (right-left+1);
}


void dfs(int start){
// cout << node_index << endl;
node[start] = USED;
int tmp[MAXN];
int top_index = -1;
for (int i = 0; i < n; i++){
if ( NOT_USED == node[i] && 0 != g[start][i]){
top_index++;
tmp[top_index] = i;
}
}
if (top_index >= 0){
// 随机选择
for (int i = 0; i < 100; i++){
int left, right;
left = get_rand(0,top_index);
right = get_rand(0,top_index);
int tmp_index = tmp[left];
tmp[left] = tmp[right];
tmp[right] = tmp_index;
}


for (int i = 0; i <= top_index; i++){
int go_index = tmp[i];
if ( NOT_USED == node[go_index]){
printf("    %d -> %d [ label=\"%d\" arrowhead=\"none\" ];\n", start, go_index, g[start][go_index]);
weight += g[start][go_index];
dfs(go_index);
}
}
}
}


int main(){
srand(time(0));
// input data
cin >> n >> cnt;
for (int i = 0; i < cnt; i++){
int a, b, val;
cin >> a >> b >> val;
g[a][b] = val;
g[b][a] = val;
}
printf("digraph G {\n");
// start from 0
dfs(0);
printf("B[label=\"%d\"];\n", weight);
printf("}\n");


return 0;

}

https://github.com/ismdeep/mst