补全9月11日至13日课评：为13名学生创建请假文档，为5个班级创建总结文档

C++代码/学习/奇怪的电梯.cpp

@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+#define endl '\n'
+using namespace std;
+
+int n, a, b;
+int cnt = 0;
+int arr[100100];
+
+int fx[] = {0, 1, -1};
+
+int q[100000][2]; // ϱê0±íʾ´ÎÊý 
+
+void bfs(int k){
+	int head = 1, tail = 1;
+	q[head][0] = 0; 
+	q[head][1] = k;
+	
+	while(head <= tail){
+		int curr = q[head][1]; //µ±Ç°Â¥²ã 
+		
+		int tx;
+		for(int i = 1; i <= 2; i++){
+			tx = curr + fx[i] * arr[curr];
+			
+			if(tx >= 1 && tx <= n){
+				tail++;
+				q[tail][0] = q[head][0] + 1;
+				q[tail][1] = tx;
+				
+				if(tx == b) {
+					cout << q[tail][0];
+					exit(0); 
+				}
+			}
+		}
+		head++;
+	}
+}
+
+int main(){
+	cin >> n >> a >> b;
+	if(a == b){
+		cout << 0;
+		return 0;
+	}
+	for(int i = 1; i <= n; i++){
+		cin >> arr[i];
+	}
+	
+	bfs(a);
+	
+	cout << -1;
+	return 0;
+}
+