diff --git a/Checker/Adapters/UOJJudger.cpp b/Checker/Adapters/UOJJudger.cpp
index fd681d9..bba8b0b 100644
--- a/Checker/Adapters/UOJJudger.cpp
+++ b/Checker/Adapters/UOJJudger.cpp
@@ -59,8 +59,6 @@ static bool readOpt(Option& opt,
                                 maxTime * 1000000));
     opt.insert("MemoryLimit", maxMem << 10);
     opt.insert("CompareMode", CompareMode::Text);
-    opt.insert("TimeSamples",
-               fs::path("CheckerDir/UOJ-Samples"));
     return true;
 }
 static bool runUOJ(const fs::path& exec) {
diff --git a/Checker/CMakeLists.txt b/Checker/CMakeLists.txt
index 5ad05ff..051a7fb 100644
--- a/Checker/CMakeLists.txt
+++ b/Checker/CMakeLists.txt
@@ -22,10 +22,6 @@ endif(NOT HAS_UNZIP)
 find_program(HAS_PERF perf)
 find_program(HAS_SYZOJTOOLS syzoj)
 
-set (CHECKER_VERSION_MAJOR 2)
-set (CHECKER_VERSION_MINOR 9)
-set (CHECKER_VERSION_PATCH 0)
-
 option(BZOJ_JUDGER "bzoj-judger" ON)
 option(LOJ_JUDGER "loj-judger" ON)
 option(UOJ_JUDGER "uoj-judger" ON)
diff --git a/Checker/Checker.cpp b/Checker/Checker.cpp
index 0700ec7..0664d82 100644
--- a/Checker/Checker.cpp
+++ b/Checker/Checker.cpp
@@ -8,10 +8,10 @@ int main() {
     std::cout.precision(2);
     std::cout << std::fixed;
 
-    line("Checker " VERSION, '*');
+    line("Checker for " CHECKER_PLATFORM " 2.9.1",
+         '*');
     std::cout << "Built at " << __TIME__ << " on "
               << __DATE__ << std::endl;
-    platformInfo();
     fs::path exec = scanExec();
     std::cout << "found program:" << exec << std::endl;
     autoRun(exec);
diff --git a/Checker/CheckerConfig.hpp.in b/Checker/CheckerConfig.hpp.in
index f0f24cb..69b83ae 100644
--- a/Checker/CheckerConfig.hpp.in
+++ b/Checker/CheckerConfig.hpp.in
@@ -1,3 +1,3 @@
-#define VERSION "@CHECKER_VERSION_MAJOR@.@CHECKER_VERSION_MINOR@.@CHECKER_VERSION_PATCH@"
+#define CHECKER_PLATFORM "@CMAKE_SYSTEM_NAME@"
 #cmakedefine USE_SYZOJTOOLS
 #cmakedefine USE_PERF
diff --git a/Checker/Platforms/Linux/PlatformLinux.cpp b/Checker/Platforms/Linux/PlatformLinux.cpp
index e10a5fd..e4fbe90 100644
--- a/Checker/Platforms/Linux/PlatformLinux.cpp
+++ b/Checker/Platforms/Linux/PlatformLinux.cpp
@@ -7,9 +7,6 @@
 #include <sys/types.h>
 #include <termios.h>
 #include <unistd.h>
-void platformInfo() {
-    system("lsb_release -d");
-}
 void initPlatform() {
     struct rlimit limit;
     getrlimit(RLIMIT_STACK, &limit);
diff --git a/Checker/Platforms/Platform.hpp b/Checker/Platforms/Platform.hpp
index 2c95fcc..6854776 100644
--- a/Checker/Platforms/Platform.hpp
+++ b/Checker/Platforms/Platform.hpp
@@ -8,6 +8,5 @@
 #include "Linux/PlatformLinux.hpp"
 #endif
 void initPlatform();
-void platformInfo();
 void reportJudgeError(const RunResult& res);
 int getConsoleWidth();
diff --git a/Checker/Platforms/Windows/PlatformWindows.cpp b/Checker/Platforms/Windows/PlatformWindows.cpp
index cc9d97d..bd00dc0 100644
--- a/Checker/Platforms/Windows/PlatformWindows.cpp
+++ b/Checker/Platforms/Windows/PlatformWindows.cpp
@@ -61,9 +61,6 @@ void initPlatform() {
         old | ENABLE_VIRTUAL_TERMINAL_PROCESSING));
     setCodePage(65001);
 }
-void platformInfo() {
-    system("ver");
-}
 static const std::string& getWinntHeader() {
     static std::string str =
         file2Str(readConfig("WinntHeader"));
diff --git a/Checker/readme.md b/Checker/readme.md
index ee24005..a2c873d 100644
--- a/Checker/readme.md
+++ b/Checker/readme.md
@@ -128,9 +128,12 @@ AC后询问OJ上的时间并加入samples中，在BZOJ计时方式下skip掉剩
 2.8.4(5.14)
 修复系统时间超时产生SIGXCPU信号，误判TLE的问题。
 
-2.9.0(5.15)
+2.9.0(5.18)
 支持UOJ题目读取与样例数据下载
 
+2.9.1(5.19)
+取消UOJ的TimeSample（样例数据与评测数据不同）
+
 ## TODO List
 
 - [x] 跨Windows平台、分离平台实现
diff --git a/OI-Source.code-workspace b/OI-Source.code-workspace
index 4ae4283..34140f9 100644
--- a/OI-Source.code-workspace
+++ b/OI-Source.code-workspace
@@ -87,7 +87,8 @@
 			"source_location": "cpp",
 			"*.idl": "cpp",
 			"hash_map": "cpp",
-			"hash_set": "cpp"
+			"hash_set": "cpp",
+			"decimal": "cpp"
 		},
 		"latex-workshop.intellisense.citation.maxfilesizeMB": 128,
 		"latex-workshop.latex.recipes": [
diff --git a/Queue.md b/Queue.md
index 288b963..c54fcef 100644
--- a/Queue.md
+++ b/Queue.md
@@ -86,6 +86,7 @@
 # minmax容斥
 - [x] LOJ#2542. 「PKUWC2018」随机游走
 - [x] LOJ#2127. 「HAOI2015」按位或（做完后作为minmax容斥的例题）
+- [ ] UOJ#449
 # FFT/NTT/FWT/生成函数
 - [x] LOJ#151. 多项式求立方根
 - [x] LOJ#2527. 「HAOI2018」染色
diff --git a/Review/Backmatter.tex b/Review/Backmatter.tex
index 3239e99..4ca4508 100644
--- a/Review/Backmatter.tex
+++ b/Review/Backmatter.tex
@@ -319,3 +319,48 @@ \subsection{day2}
 就叫我滚回去学文化课了。
 
 混了两年换来这个结果。不仅没得到想要的，还失去了许多。。。这就是人生？
+\section{End}
+2019年5月20日
+
+最后一次比赛后我就再也碰不了电子设备了，所以这里提前做个收尾。
+
+THUSC2019应该是我OI生涯中的最后一站吧。我也大概知道了结局，否则也不会花一个月的时间搞
+THUAC，甚至抽时间刷电影，这两个是我一直想做但忍着不做的事。
+
+我没能达到自己的要求，既不能留住她，也不能让自己走出失恋的阴影，从而丧失刷题的动力。
+
+我还有一堆的TODO没有做完，如果我能撑到高中毕业而没有崩溃的话，我会抽时间完成它的。但是不
+再加入新的东西。如果有学弟愿意接手这个烂摊子，可以发Pull Request给我。
+
+至于开班造学弟的事情，由于我可能上不了很好的大学，会成为反面教材，并且加上近年来moe对
+竞赛方面自主招生的打压，应该不会有家长送人来，学校也不会配合的。我能留给学弟的，只有这
+本笔记，附赠一个Checker。
+
+送给学弟们的忠告：
+\begin{itemize}
+    \item 适当地娱乐，要注意调整比例。我当时靠着鼓捣CG还能保持0娱乐，离开它后整个人
+    就变得毫无生气，离开她后就开始颓废。
+    \item 尽量组团学习，同等级OIer之间的交流可以大量节约时间，而且不会感到孤独。
+    \item 我在笔记中标记的坑，一定要记住。这是我用时间与分数换来的。
+    \item 多训练思维。在掌握笔记中的知识后，你们能做的只有裸题而已。要思考如何将考点隐藏，
+    如何转化。
+    \item 多出题。上面一条我也做不到，因为我能接触到的题目少。如果你们是组团学习的，可以考虑
+    互相出题，互相Hack，这同样是一种训练。多Hack可以熟悉出题人可以怎样卡掉某个算法。
+    \item 多打比赛。平时训练和比赛时的心理与策略是十分不同的。缺少比赛也是我的不足。
+    \item 所以说，只要人数多，你们就可以自己出题，举办校赛，赛后hack，这样的训练效果比我自己
+    一个人刷题好得多。
+    \item 同样重视数学和编程方面的训练。虽然OI侧重于算法设计，但是数学功底好就可以快速
+    推导式子，提高对语言的掌握程度可以减少bug。
+    \item 如果有事找我，请确保你的C++代码大括号不换行。其它的代码风格我可以兼容，但是大括号
+    免谈。
+\end{itemize}
+
+希望将来我校有人能完成我未能完成的梦想，最好能挑大梁，培养更多的学弟学妹。
+
+希望这本笔记对你们有一些帮助。
+
+\begin{figure}
+    \centering
+    \includegraphics[width=0.8\textwidth,clip]{mypic.jpg}
+    \caption{这应该是本笔记唯一一张图了}
+\end{figure}
diff --git a/Review/Main.tex b/Review/Main.tex
index 9a0ee9c..dc859d5 100644
--- a/Review/Main.tex
+++ b/Review/Main.tex
@@ -30,6 +30,7 @@
 \dominitoc[n]
 \usepackage{shorttoc}
 %Feature
+\usepackage{graphicx}
 \usepackage{xcolor}
 \usepackage{CJKfntef}
 \newfontfamily\CodeFont{Consolas}
diff --git a/Review/Math/Inversion.tex b/Review/Math/Inversion.tex
index 29f1698..4d8dabd 100644
--- a/Review/Math/Inversion.tex
+++ b/Review/Math/Inversion.tex
@@ -117,7 +117,7 @@ \subsubsection{期望形式}
 
 \paragraph{例题~「HAOI2015」按位或}
 记$max(S)$为状态S中最晚出现的1的出现的期望时间，$min(S)$为状态S中最早出现
-的1的出现的期望时间。$min(S)$很容易求得其表达式，考虑与$S$的交不为空集的$T$，表达式为
+的1的出现期望时间。$min(S)$很容易求得其表达式，考虑与$S$的交不为空集的$T$，表达式为
 $min(S)=\frac{1}{\displaystyle \sum_{T\cap S \neq \emptyset}{P_T}}$（根据
 伯努利试验中几何分布的期望求得，参见第~\ref{Bernoulli}节）。
 这个式子仍然不好求，可以考虑补集转换，即考虑$T$与$S$的交为空集的情况。这个条件蕴含了
diff --git a/Review/Optmize/LP.tex b/Review/Optmize/LP.tex
index dd3cf24..73056f4 100644
--- a/Review/Optmize/LP.tex
+++ b/Review/Optmize/LP.tex
@@ -198,6 +198,9 @@ \subsubsection{初始化init}
 \subsubsection{算法实现（UOJ179）}
 为了过掉UOJ的Extra Test，这里使用了两种初始化方法的混合（然而还是过不去，
 只能指望Mehrotra predictor–corrector method了）。
+
+Update：事实上应该是浮点数精度不够。
+
 \lstinputlisting{Source/Templates/SimplexSLP.cpp}
 
 \subsubsection{稀疏矩阵优化}
diff --git a/Review/mypic.jpg b/Review/mypic.jpg
new file mode 100644
index 0000000..f5e372f
Binary files /dev/null and b/Review/mypic.jpg differ
diff --git a/Source/Greed/UOJ455.cpp b/Source/Greed/UOJ455WA.cpp
similarity index 100%
rename from Source/Greed/UOJ455.cpp
rename to Source/Greed/UOJ455WA.cpp
diff --git a/Source/Network Flows/POJ2175.cpp b/Source/Network Flows/POJ2175.cpp
new file mode 100644
index 0000000..d544aa9
--- /dev/null
+++ b/Source/Network Flows/POJ2175.cpp	
@@ -0,0 +1,11 @@
+#include <cstdio>
+const int size = 105;
+struct Point {
+    int x, y, z;
+} A[size], B[size];
+int main() {
+    int n, m;
+    scanf("%d%d", &n, &m);
+
+    return 0;
+}
diff --git a/Templates/Simplex.cpp b/Templates/UOJ179-Simplex.cpp
similarity index 56%
rename from Templates/Simplex.cpp
rename to Templates/UOJ179-Simplex.cpp
index 4ebeacd..63fac7e 100644
--- a/Templates/Simplex.cpp
+++ b/Templates/UOJ179-Simplex.cpp
@@ -1,49 +1,46 @@
 #include <algorithm>
 #include <cmath>
 #include <iostream>
-int getRandom() {
-    static int seed = 2354;
-    return seed = seed * 48271LL % 2147483647;
+typedef float FT __attribute__((mode(TF)));
+const FT epsA = 1e-10, epsB = 1e-20, epsC = 1e-30,
+         zero = 0, one = 1;
+FT mabs(FT val) {
+    return val >= zero ? val : -val;
 }
-typedef long double FT;
-const FT eps = 1e-10;
 const int size = 25;
 FT A[size][size];
-int id[size * 2], n, m;
+int idn[size], idm[size], n, m;
 void pivot(int l, int e) {
-    std::swap(id[n + l], id[e]);
+    std::swap(idm[l], idn[e]);
     FT fac = A[l][e];
-    A[l][e] = 1.0;
+    A[l][e] = one;
     for(int i = 0; i <= n; ++i)
         A[l][i] /= fac;
     for(int i = 0; i <= m; ++i)
         if(i != l) {
             FT k = A[i][e];
-            A[i][e] = 0.0;
+            A[i][e] = zero;
             for(int j = 0; j <= n; ++j)
                 A[i][j] -= k * A[l][j];
         }
 }
-int q[size];
 bool init() {
+    idm[0] = idn[0] = 1 << 30;
     while(true) {
-        int qcnt = 0;
+        int l = 0;
         for(int i = 1; i <= m; ++i)
-            if(A[i][0] < -eps)
-                q[qcnt++] = i;
-        if(qcnt == 0)
-            break;
-        int l = q[getRandom() % qcnt];
-        qcnt = 0;
+            if(A[i][0] < -epsA && idm[i] < idm[l])
+                l = i;
+        if(l == 0)
+            return true;
+        int e = 0;
         for(int i = 1; i <= n; ++i)
-            if(A[l][i] < -eps)
-                q[qcnt++] = i;
-        if(qcnt == 0)
+            if(A[l][i] < -epsA && idn[i] < idn[e])
+                e = i;
+        if(e == 0)
             return false;
-        int e = q[getRandom() % qcnt];
         pivot(l, e);
     }
-    return true;
 }
 bool simplex() {
     if(!init()) {
@@ -53,21 +50,19 @@ bool simplex() {
     while(true) {
         int e = 0;
         for(int i = 1; i <= n; ++i)
-            if(A[0][i] > eps) {
+            if(A[0][i] > epsB && idn[i] < idn[e])
                 e = i;
-                break;
-            }
         if(e == 0)
             break;
-        FT minv = 1e20;
+        FT minv = 1e200;
         int l = 0;
         for(int i = 1; i <= m; ++i)
-            if(A[i][e] > eps) {
+            if(A[i][e] > epsB) {
                 FT val = A[i][0] / A[i][e];
-                if(val < minv) {
-                    minv = val;
-                    l = i;
-                }
+                if(l == 0 || val < minv ||
+                   (mabs(val - minv) < epsC &&
+                    idm[i] < idm[l]))
+                    minv = val, l = i;
             }
         if(l == 0) {
             std::cout << "Unbounded" << std::endl;
@@ -77,7 +72,20 @@ bool simplex() {
     }
     return true;
 }
-FT ans[size];
+FT ans[size * 2];
+typedef long long Int64;
+std::istream& operator>>(std::istream& in, FT& val) {
+    Int64 tmp;
+    in >> tmp;
+    val = tmp;
+    // if(static_cast<Int64>(val) != tmp)
+    //    throw;
+    return in;
+}
+typedef long double IOFT;
+std::ostream& operator<<(std::ostream& out, FT val) {
+    return out << static_cast<IOFT>(val);
+}
 int main() {
     int t;
     std::cin >> n >> m >> t;
@@ -89,14 +97,16 @@ int main() {
         std::cin >> A[i][0];
     }
     for(int i = 1; i <= n; ++i)
-        id[i] = i;
+        idn[i] = i;
+    for(int i = 1; i <= m; ++i)
+        idm[i] = n + i;
     std::cout.precision(14);
     if(simplex()) {
         std::cout << std::fixed << -A[0][0]
                   << std::endl;
         if(t) {
             for(int i = 1; i <= m; ++i)
-                ans[id[n + i]] = A[i][0];
+                ans[idm[i]] = A[i][0];
             for(int i = 1; i <= n; ++i)
                 std::cout << std::fixed << ans[i]
                           << ' ';
diff --git a/Templates/UOJ179.py b/Templates/UOJ179.py
new file mode 100644
index 0000000..681cda9
--- /dev/null
+++ b/Templates/UOJ179.py
@@ -0,0 +1,125 @@
+from decimal import *
+
+epsA = Decimal()
+epsB = Decimal()
+epsC = Decimal()
+A = [[]]
+idn = []
+idm = []
+n = 0
+m = 0
+
+
+def pivot(l, e):
+    idm[l], idn[e] = idn[e], idm[l]
+    fac = A[l][e]
+    A[l][e] = Decimal(1)
+    que = []
+    for i in range(n+1):
+        A[l][i] /= fac
+        if A[l][i] < -epsC or A[l][i] > epsC:
+            que.append(i)
+    for i in range(m+1):
+        if i != l:
+            k = A[i][e]
+            A[i][e] = Decimal(0)
+            if -epsC < k and k < epsC:
+                continue
+            for j in que:
+                A[i][j] -= k * A[l][j]
+
+
+def init():
+    while True:
+        l = -1
+        for i in range(m):
+            if A[i][n] < -epsA and idm[i] < idm[l]:
+                l = i
+        if l == -1:
+            return True
+        e = -1
+        for i in range(n):
+            if A[l][i] < -epsA and idn[i] < idn[e]:
+                e = i
+        if e == -1:
+            return False
+        pivot(l, e)
+
+
+def simplex():
+    if not init():
+        print("Infeasible")
+        return False
+
+    while True:
+        e = -1
+        for i in range(n):
+            if A[m][i] > epsB and idn[i] < idn[e]:
+                e = i
+        if e == -1:
+            return True
+        minv = Decimal(0)
+        l = -1
+        for i in range(m):
+            if A[i][e] > epsB:
+                val = A[i][n] / A[i][e]
+                if (l == -1 or val < minv
+                    or (Decimal.copy_abs(val - minv) < epsC
+                        and idm[i] < idm[l])):
+                    minv = val
+                    l = i
+        if l == -1:
+            print("Unbounded")
+            return False
+        pivot(l, e)
+
+
+def toString(val):
+    return Decimal(val).quantize(Decimal('0.00000000'))
+
+
+def mainImpl():
+    getcontext().prec = 80
+
+    global epsA
+    epsA = Decimal.from_float(1e-20)
+    global epsB
+    epsB = Decimal.from_float(1e-30)
+    global epsC
+    epsC = Decimal.from_float(1e-40)
+
+    global n
+    global m
+    n, m, t = map(int, input().split())
+
+    tmp = [Decimal(i) for i in input().split()] + [0]
+
+    global A
+    A = [[] for i in range(m)]
+    for i in range(m):
+        A[i] = [Decimal(i) for i in input().split()]
+    A.append(tmp)
+
+    inf = 1 << 30
+    global idn
+    idn = [i for i in range(n)]+[inf]
+    global idm
+    idm = [n+i for i in range(m)]+[inf]
+
+    if simplex():
+        print(toString(-A[m][n]))
+
+        if t == 1:
+            ans = [Decimal('0.0') for i in range(n+m+5)]
+            for i in range(m):
+                ans[idm[i]] = A[i][n]
+            for i in range(n):
+                print(toString(ans[i]), end=' ')
+            print()
+
+
+if __name__ == '__main__':
+    try:
+        mainImpl()
+    except Exception as err:
+        print("Exception:{0}".format(err))