BZOJ1975【左偏树】

卡Priority_queue的内存简直是不忍直视.

/* I will wait for you */
 
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <string>
#define make make_pair
#define fi first
#define se second
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef map<int, int> mii;
 
const int maxn = 200010;
const int maxm = 1010;
const int maxs = 26;
const int inf = 0x3f3f3f3f;
const int P = 1000000007;
const double eps = 1e-6;
 
inline ll read()
{
    ll x = 0, f = 1; char ch = getchar();
    while (ch < '0' || ch > '9')
          f = (ch == '-' ? -1 : 1), ch = getchar();
    while (ch >= '0' && ch <= '9')
          x = x * 10 + ch - '0', ch = getchar();
    return x * f;
}
 
typedef pair<double, pair<int, double> > Pii;
 
struct Heap
{
    Pii val; int dis, size; Heap *ls, *rs;
} *null;
 
void init()
{
    null = new Heap();
    null -> val = make(1e12, make(0, 1e12));
    null -> dis = -1, null -> size = 0;
    null -> ls = null -> rs = null;
}
 
Heap *marge(Heap *a, Heap *b)
{
    if (a == null) return b;
    if (b == null) return a;
     
    if (a -> val > b -> val) swap(a, b);
    a -> rs = marge(a -> rs, b);
     
    if (a -> ls -> dis < a -> rs -> dis)
        swap(a -> ls, a -> rs);
    a -> dis = a -> ls -> dis + 1;
    a -> size = a -> ls -> size + a -> rs -> size;
    return a;
}
 
struct _Heap
{
    Heap *Q;
    void init() {
        Q = null;
    }
    bool empty() {
        return Q -> size == 0;
    }
    Pii top() {
        return Q -> val;
    }
    void pop() {
        Heap* _del = Q; 
        Q = marge(Q -> ls, Q -> rs), delete(_del);
    }
    void push(Pii a) {
        Heap *_Q = new Heap();
        _Q -> val = a, _Q -> dis = 0, _Q -> size = 1;
        _Q -> ls = _Q -> rs = null, Q = marge(Q, _Q);
    }
} q;
 
struct edge
{
    int v; double w; int next;
} e[maxn], _e[maxn];
 
int n, m, cnt, _cnt, ans = -1, head[maxn], _head[maxn], vis[maxn];
double E, h[maxn];
 
void insert(int u, int v, double w)
{
    e[cnt] = (edge) {v, w, head[u]}, head[u] = cnt++;
}
 
void _insert(int u, int v, double w)
{
    _e[_cnt] = (edge) {v, w, _head[u]}, _head[u] = _cnt++;
}
 
void spfa()
{
    for (int i = 1; i <= n; i++)
        h[i] = i == n ? 0 : 1e12;
    queue<int> _q; _q.push(n);
         
    while (!_q.empty()) {
        int u = _q.front();
        _q.pop(), vis[u] = 0;
         
        for (int i = _head[u]; ~i; i = _e[i].next) {
            int v = _e[i].v;
            if (h[v] > h[u] + _e[i].w) {
                h[v] = h[u] + _e[i].w;
                if (!vis[v]) vis[v] = 1, _q.push(v);
            }
        }
    }
}
  
void Astar()
{
    q.init(), q.push(make(h[1], make(1, 0)));
     
    while (!q.empty() && E >= -eps) {
        Pii sta = q.top(); q.pop();
         
        int u = sta.se.fi; double w = sta.se.se;
        if (u == n) ans += 1, E -= w;
         
        for (int i = head[u]; ~i; i = e[i].next) {
            int v = e[i].v; double _w = w + e[i].w;
            q.push(make(_w + h[v], make(v, _w)));
        }
    }
}
 
int main()
{
    scanf("%d%d%lf", &n, &m, &E);
     
    memset(head, -1, sizeof head);
    memset(_head, -1, sizeof _head);
    for (int i = 1; i <= m; i++) {
        int u, v; double w; 
        scanf("%d%d%lf", &u, &v, &w);
        insert(u, v, w), _insert(v, u, w);
    }
     
    init(), spfa(), Astar();
    printf("%d\n", ans);
     
    return 0;
}