diff --git a/S2OJ/1550/1550.cpp b/S2OJ/1550/1550.cpp
new file mode 100644
index 00000000..fa71ea51
--- /dev/null
+++ b/S2OJ/1550/1550.cpp
@@ -0,0 +1,38 @@
+#include <iostream>
+#include <algorithm>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, a[N], c[N], p, ans;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    bool flag = n >= 3;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+
+        if (a[i] == n) p = i;
+    }
+
+    flag &= a[1] == n - 1 && a[n] == n;
+
+    for (int i = 1; i < p; i++) {
+        if (a[i] > a[i + 1]) {
+            ans++;
+            std::swap(a[i], a[i + 1]);
+        }
+    }
+
+    cout << static_cast<long long>(n) * (n - 1) + ans - flag << endl;
+
+    return 0;
+}
diff --git a/S2OJ/1550/data/bubble1.ans b/S2OJ/1550/data/bubble1.ans
new file mode 100644
index 00000000..38118f32
--- /dev/null
+++ b/S2OJ/1550/data/bubble1.ans
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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+size 2
diff --git a/S2OJ/1550/data/bubble1.in b/S2OJ/1550/data/bubble1.in
new file mode 100644
index 00000000..8e8c02ad
--- /dev/null
+++ b/S2OJ/1550/data/bubble1.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble10.ans b/S2OJ/1550/data/bubble10.ans
new file mode 100644
index 00000000..d4e96fee
--- /dev/null
+++ b/S2OJ/1550/data/bubble10.ans
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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+size 11
diff --git a/S2OJ/1550/data/bubble10.in b/S2OJ/1550/data/bubble10.in
new file mode 100644
index 00000000..195000f0
--- /dev/null
+++ b/S2OJ/1550/data/bubble10.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble2.ans b/S2OJ/1550/data/bubble2.ans
new file mode 100644
index 00000000..8da2bb0d
--- /dev/null
+++ b/S2OJ/1550/data/bubble2.ans
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+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble2.in b/S2OJ/1550/data/bubble2.in
new file mode 100644
index 00000000..3bbba933
--- /dev/null
+++ b/S2OJ/1550/data/bubble2.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
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+size 14
diff --git a/S2OJ/1550/data/bubble3.ans b/S2OJ/1550/data/bubble3.ans
new file mode 100644
index 00000000..ce22562b
--- /dev/null
+++ b/S2OJ/1550/data/bubble3.ans
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:969eeff1eaac226a228cc61503effa46ea87d872ef3174365befc7c36ffa3c48
+size 3
diff --git a/S2OJ/1550/data/bubble3.in b/S2OJ/1550/data/bubble3.in
new file mode 100644
index 00000000..5ae1d504
--- /dev/null
+++ b/S2OJ/1550/data/bubble3.in
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+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble4.ans b/S2OJ/1550/data/bubble4.ans
new file mode 100644
index 00000000..b3c252c9
--- /dev/null
+++ b/S2OJ/1550/data/bubble4.ans
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+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble4.in b/S2OJ/1550/data/bubble4.in
new file mode 100644
index 00000000..96038cbf
--- /dev/null
+++ b/S2OJ/1550/data/bubble4.in
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+size 1228
diff --git a/S2OJ/1550/data/bubble5.ans b/S2OJ/1550/data/bubble5.ans
new file mode 100644
index 00000000..b39ea21d
--- /dev/null
+++ b/S2OJ/1550/data/bubble5.ans
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+version https://git-lfs.github.com/spec/v1
+oid sha256:acb18536629e8c69f7c8bda33dc9893bd02c6574616c3eb7ac0ef08715e39cf2
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diff --git a/S2OJ/1550/data/bubble5.in b/S2OJ/1550/data/bubble5.in
new file mode 100644
index 00000000..4ca98772
--- /dev/null
+++ b/S2OJ/1550/data/bubble5.in
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+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble6.ans b/S2OJ/1550/data/bubble6.ans
new file mode 100644
index 00000000..8041605f
--- /dev/null
+++ b/S2OJ/1550/data/bubble6.ans
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diff --git a/S2OJ/1550/data/bubble6.in b/S2OJ/1550/data/bubble6.in
new file mode 100644
index 00000000..19d23cb3
--- /dev/null
+++ b/S2OJ/1550/data/bubble6.in
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+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble7.ans b/S2OJ/1550/data/bubble7.ans
new file mode 100644
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--- /dev/null
+++ b/S2OJ/1550/data/bubble7.ans
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+version https://git-lfs.github.com/spec/v1
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diff --git a/S2OJ/1550/data/bubble7.in b/S2OJ/1550/data/bubble7.in
new file mode 100644
index 00000000..ee4064e6
--- /dev/null
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diff --git a/S2OJ/1550/data/bubble8.ans b/S2OJ/1550/data/bubble8.ans
new file mode 100644
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--- /dev/null
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new file mode 100644
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diff --git a/S2OJ/1550/data/bubble9.ans b/S2OJ/1550/data/bubble9.ans
new file mode 100644
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new file mode 100644
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new file mode 100644
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