Agri-Net

題目連結：

解題思路：

最小生成樹！！！

AC程式碼(kruskal)：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

const int maxn = 100010;
int pa[maxn];
int n,m,sum;

struct Edge{
    int u,v,w;
}edge[maxn];

bool cmp(Edge a,Edge b){
    return a.w < b.w;
}

int Find(int x){
    if(pa[x] != x)
        pa[x] = Find(pa[x]);
    return pa[x];
}

int kruskal(){
    int u,v,cnt = n,l=0;
    for(int i = 0; i < sum; i++){
        u = Find(edge[i].u);
        v = Find(edge[i].v);
        if(u != v){
            l += edge[i].w;
            pa[v] = u;
            if(--cnt == 1)
                break;
        }
    }
    return l;
}

int main(){
    int n;
    while(scanf("%d",&n)!=EOF){
        memset(pa,-1,sizeof(pa));
        int w;
        sum = 0;
        for(int i = 0; i < n; i++)
            for(int j = 0; j < n; j++){
                scanf("%d",&w);
                if(i != j){
                    edge[sum].u = i;
                    edge[sum].v = j;
                    edge[sum++].w = w;
                }
            }
        for(int i = 0; i < sum; i++)
            pa[i] = i;
        sort(edge,edge+sum,cmp);
        printf("%d\n",kruskal());
    }
    return 0;
}
 

AC程式碼（prim）：

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;

const int INF = 0xfffffff;
int maze[110][110];
int vis[110],n;

int prime(){
    int tmp = 0,sum = 0;
    vis[0] = 1;
    for(int i = 1; i < n; i++){
        int minn = INF;
        for(int j = 0; j < n; j++)
            if(vis[j]){
                for(int k = 0; k < n; k++){
                    if(!vis[k] && maze[j][k]<minn)
                        minn=maze[j][k],tmp=k;
                }
            }
            sum += minn;
            vis[tmp] = 1;
    }
    return sum;
}

int main(){
    while(scanf("%d",&n)!=EOF){
        memset(maze,0,sizeof(maze));
        memset(vis,0,sizeof(vis));
        for(int i = 0; i < n; i++)
            for(int j = 0; j < n; j++)
                scanf("%d",&maze[i][j]);
        printf("%d\n",prime());
    }
    return 0;
}