POJ 1511 - Invitation Cards 邻接表 Dijkstra堆优化

昨天的题太水了，堆优化跑的不爽，今天换了一个题，1000000个点，1000000条边= =

试一试邻接表

写的过程中遇到了一些问题，由于习惯于把数据结构封装在 struct 里，结果 int [1000000] 导致 struct 爆栈，此问题亟待解决..

实力碾压SPFA 2500 ms，有图为证

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#define MAXP (1000000 + 10)
#define MAXQ MAXP
#define INF 2000000000
using namespace std;

struct Edge{
    int u, v, w;
}e[MAXQ];

//struct Graph{
    static int firstEdge[MAXP], cnt;
    struct E{
        int v, w, next;
        E(){}
        E(int U, int V, int W):v(V),w(W),next(firstEdge[U]){}
    }edges[MAXQ];
    inline void reset(){
        memset(firstEdge, -1, sizeof(firstEdge));
        cnt = 0;
    }
    inline void addEdge(int u, int v, int w){
        edges[cnt] = E(u, v, w);
        firstEdge[u] = cnt++;
    }
//}g;

int d1[MAXP], d2[MAXP], *d;

template <class T>
T min(T &a, T &b){
    return a < b ? a : b;
}

//struct BHeap{
    int heap[MAXP], n, index[MAXP];
    //BHeap(){}
    inline void up(int i){
        for (int j = i >> 1; j > 0; j >>= 1){
            if (d[heap[i]] < d[heap[j]]){
                swap(index[heap[i]], index[heap[j]]);
                swap(heap[i], heap[j]);
                i = j;
            }
            else break;
        }
    }
    inline void down(int i){
        for (int j = i << 1; j <= n; j <<= 1){
            j += (j < n) && (d[heap[j]] > d[heap[j + 1]]);
            if (d[heap[i]] > d[heap[j]]){
                swap(index[heap[i]], index[heap[j]]);
                swap(heap[i], heap[j]);
                i = j;
            }
            else break;
        }
    }
    inline void push(int i){
        heap[++n] = i;
        index[i] = n;
        up(n);
    }
    inline int pop(){
        if (!n) return 0;
        swap(index[heap[1]], index[heap[n]]);
        swap(heap[1], heap[n--]);
        down(1);
        return heap[n + 1];
    }
    void BHeap(int N){
        n = 0;
        for (int i = 2; i <= N; i++){
            push(i);
        }
    }
//}heap;

bool been[MAXP];

void Dijkstra(){
    memset(been, 0, sizeof(been));
    been[1] = 1;
    while (int v = pop()){
        been[v] = 1;
        for (int i = firstEdge[v]; ~i; i = edges[i].next){
            if (!been[edges[i].v]){
                if (d[edges[i].v] > d[v] + edges[i].w){
                    d[edges[i].v] = d[v] + edges[i].w;
                    up(index[edges[i].v]);
                }
            }
        }
    }
}

int main(){
    int n, p, q;
    freopen("fin.c", "r", stdin);
    scanf("%d", &n);
    while (n--){
        scanf("%d%d", &p, &q);
        for (int i = 0; i < q; i++){
            scanf("%d%d%d", &e[i].u, &e[i].v, &e[i].w);
        }
        reset();
        d = d1;
        for (int i = 1; i <= p; i++){
            d[i] = INF;
        }
        for (int i = 0; i < q; i++){
            addEdge(e[i].u, e[i].v, e[i].w);
            if (e[i].u == 1){
                d[e[i].v] = min(d[e[i].v], e[i].w);
            }
        }
        BHeap(p);
        Dijkstra();

        reset();
        d = d2;
        for (int i = 1; i <= p; i++){
            d[i] = INF;
        }
        for (int i = 0; i < q; i++){
            addEdge(e[i].v, e[i].u, e[i].w);
            if (e[i].v == 1){
                d[e[i].u] = min(d[e[i].u], e[i].w);
            }
        }
        BHeap(p);
        Dijkstra();

        long long ans = 0;
        for (int i = 2; i <= p; i++){
            ans += d1[i] + d2[i];
        }
        printf("%lld\n", ans);
    }
}