poj 1258 AgriNet

http://poj.org/problem?id=1258

　　还是简单MST，拿来测试模板的性能...

#include <cstdio>
#include <iostream>
#include <cstring>

using namespace std;
const int MAXV = 105, MAXE = 105 * 105, INF = (~0u)>>2;
struct edge{
    int t, w, next;
}es[MAXE << 1];
int h[MAXV], cnt, n, heap[MAXV << 1], size, pos[MAXV], dist[MAXV];

void init(){
    cnt = size = 0;
    memset(h, 0, sizeof(h));
    memset(heap, 0, sizeof(heap));
    memset(pos, 0, sizeof(pos));
    memset(dist, 0, sizeof(dist));
}

void addedge(int x, int y, int z){
    es[++cnt].t = y;
    es[cnt].next = h[x];
    es[cnt].w = z;
    h[x] = cnt;
}

void heapup(int k){
    while(k > 1){
        if(dist[heap[k >> 1]] > dist[heap[k]]){
            swap(pos[heap[k >> 1]], pos[heap[k]]);
            swap(heap[k >> 1], heap[k]);
            k >>= 1;
        }
        else break;
    }
}
void heapdown(int k){
    while((k << 1) <= size){
        int j;
        if((k << 1) == size || dist[heap[k << 1]] < dist[heap[k << 1 | 1]])
            j = k << 1;
        else
            j = k << 1 | 1;
        if(dist[heap[k]] > dist[heap[j]]){
            swap(pos[heap[k]], pos[heap[j]]);
            swap(heap[k], heap[j]);
            k = j;
        }
        else break;
    }
}
void push(int v, int d){
    dist[v] = d;
    heap[++size] = v;
    pos[v] = size;
    heapup(size);
}

int pop(){
    int ret = heap[1];
    swap(pos[heap[size]], pos[heap[1]]);
    swap(heap[size], heap[1]);
    size--;
    heapdown(1);
    return ret;
}

int prim(){
    int mst = 0, i, p;

    push(1, 0);
    for(i = 2; i <= n; i++)
        push(i, INF);
    for(i = 1; i <= n; i++){
        int t = pop();
        mst += dist[t];
        pos[t] = -1;
        for(p = h[t]; p; p = es[p].next){
            int dst = es[p].t;
            if(pos[dst] != -1 && dist[dst] > es[p].w){
                dist[dst] = es[p].w;
                heapup(pos[dst]);
                heapdown(pos[dst]);
            }
        }
    }
    return mst;
}

void deal(){
    int c;

    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= n; j++){
            scanf("%d", &c);
            if (i != j){
                addedge(i, j, c);
            }
        }
    }
    printf("%d\n", prim());
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("in", "r", stdin);
#endif
    while (~scanf("%d", &n)){
        init();
        deal();
    }

    return 0;
}

——written by Lyon