Chinshyo @ 2023-08-14 10:01:13
我直接小根堆优化的dij+二分(找钱的方案),用的第二篇题解的思路
昨天调到今天力,有点崩溃了
#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 100005, M = 100005;
ll f[N], dis[N], n, m, b;
bool vis[N];
int head[N], ver[M], edge[M], nxt[M], num = 0; //Chain Forward Star
void add(int x, int y, int c) {
ver[++num] = y, edge[num] = c;
nxt[num] = head[x], head[x] = num;
}
priority_queue < pair<ll, int> > q;
bool chk(ll cst) {
for(int i = 1; i <= n; i++) {
dis[i] = LONG_LONG_MAX;
vis[i] = 0;
}
q.push(make_pair(0, 1));
dis[1] = 0;
if(f[1] > cst) return false;
while(!q.empty()) {
pair <ll, int> p = q.top();
q.pop();
ll dist = -p.first, x = p.second;
if(x == n) {
if(dis[n] > b) return false;
return true;
}
if(vis[x]) continue;
vis[x] = true;
for(int i = head[x]; i > 0; i = nxt[i]) {
ll y = ver[i], c = edge[i];
if(dist + c <= dis[y] && f[y] <= cst) {
dis[y] = dist + c;
// cout << y << "》》"<< dis[y] << endl;
q.push(make_pair(-dis[y], y));
}
}
}
// for(int i = 1; i <= n; i++)
// cout << dis[i] << " ";
// cout << endl;
// if(dis[n] < cst) return true;
// return false;
}
int main() {
// freopen("a.aaa" , "w", stdout);
cin >> n >> m >> b;
for(int i = 1; i <= n; i++) cin >> f[i];
int x, y, c;
for(int i = 1; i <= m; i++) {
cin >> x >> y >> c;
add(x, y, c);
add(y, x, c);
}
long long l = 1, r = 1000000005;
if(!chk(r)) {
cout << "AFK" << endl;
return 0;
}
long long mid = (l + r) >> 1;
while(l <= r) {
bool tmp = chk(mid);
// cout << l << " " << r << " " << tmp<< endl;
if(tmp == 1) {
// cout << " Hello " << r << endl;
r = mid - 1;
mid = (l + r) >> 1;
} else {
l = mid + 1;
mid = (l + r) >> 1;
}
}
cout << l << endl;
return 0;
}
by ZXN2023 @ 2023-08-14 10:18:32
小草神,欸嘿嘿