diff --git a/1771_systemnumby/Readme.md b/1771_systemnumby/Readme.md
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+# 标题
+
+* 内容
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diff --git a/1771_systemnumby/doc/Readme.md b/1771_systemnumby/doc/Readme.md
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+# R进制高精度乘法
+
+题目描述  
+　　计算R（2<=R<=36）进制下两个高精度数的乘法，这两个数的位数均不超过100位，并输出结果（R进制，A=10，B=11，C=12，......，Z=35），输入输出中涉及到的英文字母均为大写格式字母。  
+
+输入输出格式  
+输入格式：  
+　　三行，第一行，R。第二、三行分别为用字符串表达的两个高精度数。  
+输出格式：  
+　　一行，结果值。
+
+输入输出样例  
+输入样例#1：  
+8  
+3  
+3  
+输出样例#1：  
+11  
+提示信息  
+　　直接以R进制进位进行运算。
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diff --git a/1771_systemnumby/main.cpp b/1771_systemnumby/main.cpp
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+++ b/1771_systemnumby/main.cpp
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+#include <iostream>
+
+int main()
+{
+    std::cout << "Hello Easy C++ project!" << std::endl;
+}
diff --git a/1771_systemnumby/main.exe b/1771_systemnumby/main.exe
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index 0000000..fc4df42
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diff --git a/1771_systemnumby/systemnumby.cpp b/1771_systemnumby/systemnumby.cpp
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+++ b/1771_systemnumby/systemnumby.cpp
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+#include <cstring>
+#include <iostream>
+using namespace std;
+int main()
+{
+    int n, a[101] = { 0 }, b[101] = { 0 }, c[201] = { 0 }, lena, lenb, lenc = 0;
+    string a1, b1;
+    cin >> n >> a1 >> b1;
+    lena = a1.size();
+    lenb = b1.size();
+    for (int i = 0; i < lena; i++) {
+        if (a1[i] >= 'A') {
+            a1[i] = a1[i] - 'A' + '9' + 1;
+        }
+        a[lena-i-1] = a1[i] - '0';
+    }
+    for (int i = 0; i < lenb; i++) {
+        if (b1[i] >= 'A') {
+            b1[i] = b1[i] - 'A' + '9' + 1;
+        }
+        b[lenb-1-i] = b1[i] - '0';
+    }
+    for (int i = 0; i < lena; i++) {
+        for (int j = 0; j < lenb; j++) {
+            c[i + j] += a[i] * b[j];
+            c[i + j + 1] += c[i + j] / n;
+            c[i + j] %= n;
+        }
+    }
+    int len = lena + lenb;
+    while(c[len-1]==0&&len>0){
+        len--;
+    }
+    while (len > 0) {
+        --len;
+        if (c[len] > 9) {
+            char c1 = c[len] - 10 + 'A';
+            cout << c1;
+        } else {
+            cout << c[len];
+        }
+    }
+}
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diff --git a/1771_systemnumby/systemnumby.exe b/1771_systemnumby/systemnumby.exe
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index 0000000..731c32d
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diff --git a/1771_systemnumby/test/in.txt b/1771_systemnumby/test/in.txt
new file mode 100644
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--- /dev/null
+++ b/1771_systemnumby/test/in.txt
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+8
+3
+3
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diff --git a/1771_systemnumby/test/in2.txt b/1771_systemnumby/test/in2.txt
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index 0000000..30b7665
--- /dev/null
+++ b/1771_systemnumby/test/in2.txt
@@ -0,0 +1,3 @@
+16
+88
+88
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diff --git a/1771_systemnumby/test/in3.txt b/1771_systemnumby/test/in3.txt
new file mode 100644
index 0000000..e7bbf11
--- /dev/null
+++ b/1771_systemnumby/test/in3.txt
@@ -0,0 +1,3 @@
+16
+A1A
+B2B
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diff --git a/1771_systemnumby/test/in4.txt b/1771_systemnumby/test/in4.txt
new file mode 100644
index 0000000..aeccc59
--- /dev/null
+++ b/1771_systemnumby/test/in4.txt
@@ -0,0 +1,3 @@
+16
+2
+7
\ No newline at end of file
diff --git a/1771_systemnumby/test/in5.txt b/1771_systemnumby/test/in5.txt
new file mode 100644
index 0000000..703a54d
--- /dev/null
+++ b/1771_systemnumby/test/in5.txt
@@ -0,0 +1,3 @@
+16
+1A
+1A
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diff --git a/1771_systemnumby/test/out.txt b/1771_systemnumby/test/out.txt
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index 0000000..2dc4eb6
--- /dev/null
+++ b/1771_systemnumby/test/out.txt
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+## z:\Chao\src\1771_systemnumby\test\in.txt 
+2020/03/24 周二 13:43:26.46 
+11
+-----------------------------------------------
+Process exited after 160 ms with return value 0
+
+## z:\Chao\src\1771_systemnumby\test\in2.txt 
+2020/03/24 周二 13:43:26.46 
+4840
+-----------------------------------------------
+Process exited after 90 ms with return value 0
+
+## z:\Chao\src\1771_systemnumby\test\in3.txt 
+2020/03/24 周二 13:43:26.46 
+70D05E
+-----------------------------------------------
+Process exited after 90 ms with return value 0
+
+## z:\Chao\src\1771_systemnumby\test\in4.txt 
+2020/03/24 周二 13:43:26.46 
+E
+-----------------------------------------------
+Process exited after 80 ms with return value 0
+
+## z:\Chao\src\1771_systemnumby\test\in5.txt 
+2020/03/24 周二 13:43:26.46 
+2A4
+-----------------------------------------------
+Process exited after 80 ms with return value 0
+