【數據結構】最小生成樹MST克魯斯卡爾算法實現

#include<iostream>
#include<algorithm>
using namespace std;
const int MAX = 1000;
int v, n; // 頂點數與邊數
int flag[MAX/2]; // 連通分量標識符
struct Edge {
    int v, w;
    int weight;
}Edge[MAX], MST[MAX/2];

// 邊權重排序
bool cmp(struct Edge e1, struct Edge e2) {
    return e1.weight < e2.weight;
}

void InitGraph() {
    cin>>v>>n;
    for (int i = 0; i < v; i++) {
        flag[i] = i;
    }
    for (int i = 0; i < n; i++) {
        cin>>Edge[i].v>>Edge[i].w>>Edge[i].weight;
    }
    sort(Edge, Edge + n, cmp);
}

// 判別連通分量是否連通
int Find(int p){
    return flag[p];
}

void Union(int p, int q){
    int pID = Find(p), qID = Find(q);
    if (pID == qID)
        return;
    for (int i = 0; i < n; i++)
        if (flag[i] == pID)
            flag[i] = qID;
}


bool connected(int i, int j){
    return Find(i) == Find(j);
}

// 克魯斯卡爾算法
void Kruskal() {
    int numS = v, i = 0; // numS爲連通分量個數
    cout<<"MST"<<endl;
    while (numS > 1) {
        int v = Edge[i].v, w = Edge[i].w;
        if (!connected(v, w)) {
            Union(v, w);
            cout<<Edge[i].v<<" "<<Edge[i].w<<" "<<Edge[i].weight<<endl;
            numS--;
        }
        i++;
    }
}

int main() {
    InitGraph();
    Kruskal();
    return 0;
}

// 測試樣例
6 10
0 1 6
0 2 1
0 3 5
1 2 5
1 4 3
2 3 5
2 4 6
2 5 4
3 5 2
4 5 6

// 測試結果
MST
0 2 1
3 5 2
1 4 3
2 5 4
1 2 5