poj2395 Out of Hay , 求MST的最长边

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求MST的最长边~

prim

#include <cstdio>#include <cstring>#include <vector>#include <algorithm>#define Min(a,b) (a)<(b)?(a):(b)using namespace std;const int INF = 1000000000;const int maxn = 2000 + 5;struct pto{    int v, len;};vector<pto> G[maxn];bool vis[maxn];int dis[maxn];int n, m;int Prim(){    int i, j, p, ans, minc;    memset(vis, 0, sizeof vis );    for(i=1; i<=n; ++i) dis[i] = INF;    dis[1] = 0;    ans = 0;    int maxx = -100;    for(i=1; i<=n; ++i)    {        minc = INF, p = -1;        for(j=1; j<=n; ++j) if(!vis[j])            if(minc>dis[j]) minc = dis[p=j];        if(-1 == p) break;        vis[p] = 1;        if(maxx <minc) maxx = minc;        for(j=0; j<G[p].size(); ++j) if(!vis[G[p][j].v])        {            int& u = G[p][j].v;            dis[u] = Min(dis[u], G[p][j].len);        }    }    return maxx;}int main(){    int i, x, y, z;    pto e;    while(~scanf("%d%d",&n,&m))    {        for(i=0; i<=n; ++i) G[i].clear();        for(i=0; i<m; ++i)        {            scanf("%d%d%d",&x,&y,&z);            e.v = y, e.len = z;            G[x].push_back(e);            e.v = x;            G[y].push_back(e);        }        printf("%d\n",Prim());    }    return 0;}

kruskal

#include <cstdio>#include <cstring>#include <vector>#include <algorithm>using namespace std;const int INF = 1000000000;const int maxn = 2000 + 5;const int maxm = 10000 + 5;struct Edge {    int x, y, w;    Edge(int x=0, int y=0, int w=0):x(x),y(y),w(w) {}    bool operator < (const Edge& rhs) const {        return w < rhs.w;    }} e[maxm];int fa[maxn];int n, m;int getfather(int x){    while(x != fa[x])        x = fa[x];    return fa[x];}int kruskal(){    int i, t1, t2, ans = 0, num = 0;    int maxx = -100;    sort(e, e+m);    for(i=1; i<=n; ++i) fa[i] = i;    for(i=0; i<m; ++i) {        t1 = getfather(e[i].x);        t2 = getfather(e[i].y);        if(t1 != t2) {            fa[t1] = t2;            ans += e[i].w;            if(maxx<e[i].w) maxx = e[i].w;            if(++num==n-1) break;        }    }    return maxx;}int main(){    int i, x, y, z;    while(~scanf("%d%d",&n,&m)) {        for(i=0; i<m; ++i) {            scanf("%d%d%d",&e[i].x, &e[i].y, &e[i].w);        }        printf("%d\n", kruskal());    }    return 0;}

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