蒟蒻46分求教

#include <bits/stdc++.h>
using namespace std; 
typedef long long LL; 
const int maxn = 1e4 + 100;
const int maxm = 5e4 + 100; 

inline LL min(LL aa, LL bb) { return aa < bb ? aa : bb; }
inline LL max(LL aa, LL bb) { return aa > bb ? aa : bb; }

template <typename T>
inline void read(T &s) {
	s = 0; 
	T w = 1, ch = getchar(); 
	while (!isdigit(ch)) { if (ch == '-') w = -1; ch = getchar(); }
	while (isdigit(ch)) { s = (s << 1) + (s << 3) + (ch ^ 48); ch = getchar(); }
	s *= w; 
}

template <typename T>
inline void write(T s) {
	T w = 0, ch[15]; 
	if (s < 0) putchar('-'), s = -s; 
	while (s) { ch[++w] = s % 10 + 48; s /= 10; }
	while (w) { putchar(ch[w--]); } 
}

int n, m, b, tot; 
int lin[maxn];
LL l ,r; 
LL val[maxn], dis[maxn];
bool vis[maxn];  
struct node { int next, to; LL dis; } edge[maxm << 1]; 
queue <int> q; 

inline void add(int from, int to, LL dis) {
	edge[++tot].to = to; 
	edge[tot].dis = dis; 
	edge[tot].next = lin[from]; 
	lin[from] = tot; 
}

bool spfa(LL k) {
	memset(dis, 0x3f, sizeof(dis)); 
	memset(vis, false, sizeof(vis)); 
	q.push(1); 
	vis[1] = true; 
	dis[1] = 0; 
	while (!q.empty()) {
		int x = q.front(); q.pop(); vis[x] = false; 
		for (int i = lin[x]; i; i = edge[i].next) {
			int y = edge[i].to; 
			if (dis[y] > dis[x] + edge[i].dis) {
				dis[y] = dis[x] + edge[i].dis; 
				if (!vis[y] && val[y] <= k) {
					q.push(y); 
					vis[y] = true; 
				}
			}
		}
	}
	if (dis[n] >= b) return false; 
	else return true; 
}

int main() { 
	read(n), read(m), read(b);
	for (int i = 1; i <= n; ++i) {
		read(val[i]);
		r = max(r, val[i]); 
	}
	l = max(val[1], val[n]);  
	for (int i = 1; i <= m; ++i) { 
		int x, y, z; 
		if (x == y) continue; 
		read(x), read(y), read(z); 
		add(x, y, z); 
		add(y, x, z); 
	} 
	if (!spfa(1000010000)) { 
		puts("AFK"); 
		return 0;  
	} 
	else { 
		while (l <= r) { 
			int mid = (l + r) / 2; 
			if (spfa(mid)) r = mid - 1; 
			else l = mid + 1; 
		} 
		write(l); puts("");  
	}
	return 0;  
}