Slim Span UVA

Think:
1Kruskal算法生成最小树
2题意理解:
1>生成一颗最小树使得他的边的最大权值减去边的最小权值最小
3思路:从权值最小的边出发建立最小生成树，不断更新生成的最小树的苗条度(边的最大权值减去边的最小权值)

vjudge题目链接

以下为Accepted代码

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;struct node {    int a, b;    int w;}edg[5400];bool cmp(node a, node b){    return a.w < b.w;}int n, m, f[144];void Init();bool merge(int u, int v);int get_f(int x);int main(){    int i, j, ans, cnt, sum;    bool flag;    while(scanf("%d %d", &n, &m) && (n || m)){        for(i = 1; i <= m; i++)            scanf("%d %d %d", &edg[i].a, &edg[i].b, &edg[i].w);        sort(edg+1, edg+m+1, cmp);        ans = 19980414;        for(i = 1; i <= m; i++){            Init();            cnt = 0, flag = false;            for(j = i; j <= m; j++){                if(merge(edg[j].a, edg[j].b)){                    cnt++;                }                if(cnt == n-1){                    sum = edg[j].w - edg[i].w;                    ans = min(ans, sum);                    flag = true;                    break;                }            }            if(!flag)                break;        }        if(ans != 19980414) printf("%d\n", ans);        else printf("-1\n");    }    return 0;}void Init(){    for(int i = 1; i <= n; i++)        f[i] = i;}bool merge(int u, int v){    int t1 = get_f(u);    int t2 = get_f(v);    if(t1 != t2){        f[t2] = t1;        return true;    }    else return false;}int get_f(int x){    if(f[x] == x)        return x;    else {        f[x] = get_f(f[x]);        return f[x];    }}