diff --git a/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.cpp b/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.cpp
index bcda424..8651e3d 100644
--- a/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.cpp
+++ b/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.cpp
@@ -1,12 +1,69 @@
 #include <bits/stdc++.h>
 using namespace std;
+const int INF = 0x3f3f3f3f;
 const int N = 110;
 double a[N];
+int n;
+int f1[N], f2[N];
 int main() {
     cin >> n;
     for (int i = 1; i <= n; i++) cin >> a[i];
     // 以每棵树为保留的，并且是最高的那棵树，分别求出最长上升序列长度x 和 最长下降序列长度y， x+y-1就是最终保留的整体序列长度，
     // 去掉的数量就是 n-(x+y-1)的值。然后求min()
     // 需要注意的是默认值设置为-1，比如 5 4 3 2 1 ,我们取哪棵为最高点都行不通，不存在左侧上侧到峰值的情况，右侧即使符合也不行的。
+
+    // 求最长上升
+    for (int i = 1; i <= n; i++) {
+        f1[i] = 1;
+        for (int j = 1; j < i; j++)
+            if (a[i] > a[j]) f1[i] = max(f1[i], f1[j] + 1);
+    }
+    // 求最长下降
+    for (int i = n; i >= 1; i--) {
+        f2[i] = 1;
+        for (int j = n; j > i; j--)
+            if (a[i] > a[j]) f2[i] = max(f2[i], f2[j] + 1);
+    }
+
+    // // 输出最长上升
+    // for (int i = 1; i <= n; i++) cout << f1[i] << " ";
+    // cout << endl;
+
+    // // 输出最长下降
+    // for (int i = 1; i <= n; i++) cout << f2[i] << " ";
+    // cout << endl;
+
+    bool flag = true;
+    for (int i = 1; i <= n; i++)
+        if (f1[i] != 1) {
+            flag = false;
+            break;
+        }
+
+    if (flag) {
+        cout << -1 << endl;
+        exit(0);
+    }
+
+    flag = true;
+    for (int i = 1; i <= n; i++)
+        if (f2[i] != 1) {
+            flag = false;
+            break;
+        }
+
+    if (flag) {
+        cout << -1 << endl;
+        exit(0);
+    }
+
+    int mi = -1;
+    for (int i = 1; i <= n; i++) {
+        int tmp = f1[i] + f2[i];
+        mi = max(mi, tmp);
+    }
+
+    cout << n - mi + 1 << endl;
+
     return 0;
 }
\ No newline at end of file
diff --git a/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.in b/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.in
new file mode 100644
index 0000000..744f653
--- /dev/null
+++ b/TangDou/LanQiaoBei/LanQiao14STEMA202301/BC5.in
@@ -0,0 +1,2 @@
+10
+1.0 2.3 1.2 1.7 1.1 2.0 1.8 1.8 1.2 1.9
\ No newline at end of file