dijkstra+heap

手写堆

#include 
#include 
#include 
#include 
using namespace std;
int n,p,c,num;
const int maxn = 2000;
const int maxm = 3000;
int tot,head[maxn],pos[maxn],cnt;
int ans = (1<<30);
struct node{
    int v,w,next;
}edges[maxm];

void add(int u,int v,int w){
    edges[tot].v = u;edges[tot].w = w;edges[tot].next = head[v];head[v] = tot++;
    edges[tot].v = v;edges[tot].w = w;edges[tot].next = head[u];head[u] = tot++;
}

void init(){
    memset(head,-1,sizeof(head));
    scanf("%d%d%d",&n,&p,&c);
    for(int i = 1 ; i <= n ; i++){
        scanf("%d",&pos[i]);
    }
    for(int j = 0 ; j < c; j++){
        int u,v,w;
        scanf("%d%d%d",&u,&v,&w);
        add(u,v,w);
    }
}
struct np{
    int pp;
    int ww;
}heap[maxm];
int index[maxn];

void up_heap(int no,int dis){
    int tmp = index[no];
    while((tmp>>1) >= 1 && dis < heap[tmp>>1].ww){
        heap[tmp].ww = heap[tmp>>1].ww;
        heap[tmp].pp = heap[tmp>>1].pp;
        index[heap[tmp>>1].pp] = tmp;
        tmp >>= 1;
    }
    heap[tmp].ww = dis;
    heap[tmp].pp = no;
    index[no] = tmp;
}

void down_heap(int no,int dis){
    int tmp = index[no];
    while((tmp << 1) < cnt &&(dis > heap[tmp<<1].ww || dis > heap[tmp<<1|1].ww )){
        int k = heap[tmp<<1].ww > heap[tmp <<1 |1].ww ? tmp*2+1:tmp*2;
        heap[tmp].ww = heap[k].ww;
        heap[tmp].pp = heap[k].pp;
        index[heap[k].pp] = tmp;
        tmp = k;
    }
    heap[tmp].ww = dis;
    heap[tmp].pp = no;
    index[no] = tmp;
}

void swap_heap(int i,int j){
    index[heap[i].pp ] = j;
    index[heap[j].pp ] = i;
    swap(heap[i],heap[j]);
}

void dijkstra(int ct){
    cnt = 1;
    for(int i = 1; i <= p +1 ; i++){
        if(i == ct) continue;
        //cout <<"i = "<1<<30);
        index[i] = cnt++;
    }
    heap[cnt].pp = ct;
    heap[cnt].ww = 0;
    index[ct] = cnt;
    cnt = p-1;
    for(int i = 1; i <= p ; i++){
        for(int k = head[ct] ; k != -1; k = edges[k].next){
            int v = edges[k].v;//cout << heap[index[5]].ww <<"   "<index[1]].ww<if(index[v] < p && heap[index[v]].ww > heap[index[ct]].ww+edges[k].w){
                //删除这个，加入新权值
               // printf("v = %d  pre [%d[ = %d\n",v,ct,heap[index[ct]].ww+edges[k].w);
                up_heap(v,heap[index[ct]].ww+edges[k].w);
            }
        }
        ct = heap[1].pp;
        swap_heap(1,cnt);
        swap_heap(cnt,cnt+1);
        --cnt;
        down_heap(heap[1].pp,heap[1].ww);
    }

}

void sov(){
    for(int i = 1 ; i <= p ; i++){
        dijkstra(i);
        int sum = 0;
        for(int j  = 1; j <= n ; j++){
            if(pos[j] == i) continue;
            sum += heap[index[pos[j]]].ww;
            //printf("sm[%d] = %d\n",pos[j],heap[index[pos[j]]].ww);
        }
       // cout <printf("%d\n",ans);
}

int main(){
    init();
    sov();
}