kruskal_poj 1251Jungle Roads

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poj1251

http://poj.org/problem?id=1251

此题一看就知是最小生成树，由于数据量很小，输入的数据形式也没有那一种比较方便，所以prim和kruskal都可以

下面给出kruskal代码

#include<cstdio>#include<vector>#include<cstring>#include<algorithm>#include<iostream>#define MAXEN 200#define MAXVN 60using namespace std;typedef struct{    int u, v, value;}Edge;Edge eg[MAXEN];int p[MAXVN], rank[MAXVN];vector<Edge> usedEdge;void MAKE_SET(int x){    p[x] = x;    rank[x] = 0;}int FIND_SET(int x){    if(x != p[x])        p[x] = FIND_SET(p[x]);    return p[x];}void LINK(int x, int y){    if(rank[x] > rank[y])  p[y] = x;    else{        p[x] = y;        if(rank[x] == rank[y]) rank[y] += 1;    }}void UNION_SET(int x, int y){    LINK(FIND_SET(x), FIND_SET(y));}int cmp(const void *a, const void *b){    return (*(Edge *)a).value - (*(Edge *)b).value;}bool cp(Edge a,Edge b){    return a.value < b.value;}int kruskal(int en, int vn){    usedEdge.clear();//printf("sfdds");    for(int i = 1; i <= vn; i++) MAKE_SET(i);    qsort(eg,en,sizeof(eg[0]), cmp);    for(int i = 0; i < en; i++){        if(FIND_SET(eg[i].u) != FIND_SET(eg[i].v)){            UNION_SET(eg[i].u,eg[i].v);            usedEdge.push_back(eg[i]);        }    }    int sum = 0;    for(int i = 0; i < usedEdge.size(); i++) sum+=usedEdge[i].value;    return sum;}int main(){    int vn,n, b;    char a;    //freopen("in.txt", "r", stdin);    //freopen("out.txt", "w", stdout);    while(cin>>vn && vn){        //getchar();        int count = 0;        for(int i = 1; i < vn; i++){            cin>>a>>n;            //printf("n: %d\n", n);            //getchar();            for(int j = 0; j < n ; j++){                cin>>a>>b;                getchar();                eg[count].u = i;                eg[count].v = a - 'A' +1;                eg[count++].value = b;            }        }        int sum = kruskal(count, vn);        cout<<sum<<endl;    }}