diff --git a/190523/wangmin/pg42746.cpp b/190523/wangmin/pg42746.cpp
new file mode 100644
index 0000000..2fbd7a5
--- /dev/null
+++ b/190523/wangmin/pg42746.cpp
@@ -0,0 +1,28 @@
+#include <string>
+#include <vector>
+#include <algorithm>
+#include <iostream>
+
+using namespace std;
+
+bool func(string a, string b){
+    return a+b > b+a ? true : false;
+}
+
+string solution(vector<int> numbers) {
+    string answer = "";
+    vector<string> str;
+    for(int i = 0 ; i < numbers.size(); i++){
+        str.push_back(to_string(numbers[i]));
+    }
+    
+    sort(str.begin(), str.end(), func);
+    for(int i = 0; i < str.size(); i++){
+        answer += str[i];
+    }
+    if(answer[0] == '0'){
+        return "0";
+    }
+
+    return answer;
+} 
\ No newline at end of file
diff --git a/190524/wangmin/pg42747.cpp b/190524/wangmin/pg42747.cpp
new file mode 100644
index 0000000..8d1425a
--- /dev/null
+++ b/190524/wangmin/pg42747.cpp
@@ -0,0 +1,21 @@
+#include <string>
+#include <vector>
+#include <algorithm>
+#include <iostream>
+
+using namespace std;
+
+int solution(vector<int> citations) {
+    int h;
+    sort(citations.begin(),citations.end());
+    for(int i = 0; i< citations.size(); i++){
+        h = citations.size()-i;
+
+        if(citations[i] >= h){
+            return h;
+        }
+
+    }
+    return 0;
+}
+
diff --git a/190527/wangmin/pg42840.cpp b/190527/wangmin/pg42840.cpp
new file mode 100644
index 0000000..941df3c
--- /dev/null
+++ b/190527/wangmin/pg42840.cpp
@@ -0,0 +1,49 @@
+#include <string>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+vector<int> solution(vector<int> answers) {
+    vector<int> one = {1,2,3,4,5};
+    vector<int> two = {2,1,2,3,2,4,2,5};
+    vector<int> three = {3,3,1,1,2,2,4,4,5,5};
+    
+    int oneCount = 0;
+    int twoCount = 0;
+    int threeCount = 0;
+
+    for(int i = 0; i < answers.size(); i++){
+        if(answers[i] == one[i%one.size()]){
+            oneCount++;
+        }
+    }
+
+    int max = oneCount;
+
+    for(int i = 0; i < answers.size(); i++){
+        if(answers[i] == two[i%two.size()]){
+            twoCount++;
+        }
+    }
+
+    max = (twoCount > max) ? twoCount : max;
+
+    for(int i = 0; i < answers.size(); i++){
+        if(answers[i] == three[i%three.size()]){
+            threeCount++;
+        }
+    }
+    
+    max = (threeCount > max) ? threeCount : max;
+    
+    
+    
+    vector<int> answer;
+    if(max == oneCount) answer.push_back(1);
+    if(max == twoCount) answer.push_back(2);
+    if(max == threeCount) answer.push_back(3);
+
+
+    return answer;
+}
\ No newline at end of file
diff --git a/190530/wangmin/bj1913.cpp b/190530/wangmin/bj1913.cpp
new file mode 100644
index 0000000..af70292
--- /dev/null
+++ b/190530/wangmin/bj1913.cpp
@@ -0,0 +1,53 @@
+//https://www.acmicpc.net/problem/1913
+
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+int main () {
+    int n,a;
+    cin >> n >> a;
+
+    vector<vector<int>> vec = vector<vector<int>>(n,(vector<int>(n,0)));
+
+    vector<int> start ={n/2,n/2};
+    vector<vector<int>> right = {{-1,0},{0,1},{1,0},{0,-1}};
+    vector<int> head = {-1,0};
+
+    vector<int> aindex = {0,0};
+
+    // vec[start[0]][start[1]] = 1;
+    int rightindex = 0;
+    for(int i = 1; i <= n*n; i ++){
+        // vec[start[0],start[1]]
+        vec[start[0]][start[1]] = i;
+
+        if(i == a){
+            aindex = {start[0],start[1]};
+        }
+
+        if(vec[start[0]+right[rightindex%4][0]][start[1]+right[rightindex%4][1]] == 0){
+            head = right[rightindex%4];
+            start[0] = start[0]+head[0];
+            start[1] = start[1]+head[1];
+            rightindex++;
+        }else{
+            start[0] = start[0]+head[0];
+            start[1] = start[1]+head[1];
+        }
+    }
+
+    for(int i = 0; i < n; i++){
+        for(int j = 0; j < n; j++){
+            cout << vec[i][j]<<" ";
+        }
+        cout << "\n";
+    }
+
+    cout << aindex[0]+1 << " " << aindex[1]+1<<endl;
+
+
+
+
+}
\ No newline at end of file