bfs写的58分 换成dijkstra就过了

//58分bfs
#include<bits/stdc++.h>
using namespace std;

int n,a,b,k[205];

struct node{
	int f,s;
};

bool vis[205];

void bfs(int st,int t) {
	queue<node> q;
	q.push({st,0});
	vis[st] = true;
	while(!q.empty()) {
		node x = q.front();
		q.pop();
		int floor = x.f;
		int step = x.s;
		if(floor == t) {
			cout << step;
			return;
		}
		int up = floor + k[floor];
		int down = floor - k[floor];
		if(!vis[up] && up <= t) {
			q.push({up,step+1});
			vis[up] = true;
		}else {
			if(!vis[down] && down >= 1) {
				q.push({down,step+1});
				vis[down] = true;
			}else {
				cout << -1;
				return;
			}	
		}
	}
}

int main() {
	cin >> n >> a >> b;
	for(int i = 1;i<=n;i++) {
		cin >> k[i];
	}
	bfs(a,b);
	return 0;
}

//满分dijkstra
#include<bits/stdc++.h>
using namespace std;

const int N = 250;

int n,s,k,dis[N];

vector<pair<int,int> > e[N];

priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > q;

bool vis[N];

void dijkstra(int s) {
	q.push({0,s});
	dis[s] = 0;
	while(!q.empty()) {
		int d = q.top().first;
		int u = q.top().second;
		q.pop();
		if(vis[u]) continue;
		vis[u] = 1;
		for(auto it : e[u]) {
			int v = it.first;
			int w = it.second;
			if(dis[v] > dis[u] + w) {
				dis[v] = dis[u] + w;
				q.push({dis[v],v});
			}
		}
	}
}

int main() {
	cin >> n >> s >> k;
	for(int i = 1;i<=n;i++) {
		int x;
		cin >> x;
		if(i + x <= n) {
			e[i].push_back({i + x,1});
		}
		if(i - x >= 1) {
			e[i].push_back({i - x,1});
		}
		dis[i] = 1e9;
	}
	dijkstra(s);
	if(dis[k] == 1e9) {
		cout << -1;
	}else {
		cout << dis[k];
	}
	return 0;
}

bfs求调