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diff --git a/problems/1181/21500426.cpp b/problems/1181/21500426.cpp
new file mode 100644
index 0000000..7e994b3
--- /dev/null
+++ b/problems/1181/21500426.cpp
@@ -0,0 +1,42 @@
+#include <iostream>
+#include <string>
+#include <algorithm>
+#include <vector>
+
+using namespace std;
+bool compare (string& first, string& second) {
+	return first.size() < second.size();
+}
+int main () {
+	vector <string> words;
+	vector <string>::iterator stash;
+	int N, i, j = 0;
+	string word = "";
+	cout << "how many words? ";
+	cin >> N;
+	
+	/* push data to vector */
+	for(i = 0; i < N; i++) {
+		cout << "enter the word : ";
+		cin >> word;
+		words.push_back(word);
+	}
+
+
+	/* sort */
+	sort(words.begin(), words.end());
+
+	/* remove duplicates */
+	words.erase(unique(words.begin(), words.end()), words.end());
+
+	/* sort by length */
+	sort(words.begin(), words.end(), compare);
+
+	/* print */
+	for(i = 0; i < words.size(); i++) {
+		cout << words[i] << endl;
+	}
+
+	return 0;
+}
+
diff --git a/problems/2108/21500426.cpp b/problems/2108/21500426.cpp
new file mode 100644
index 0000000..f90247c
--- /dev/null
+++ b/problems/2108/21500426.cpp
@@ -0,0 +1,104 @@
+#include <iostream>
+#include <algorithm>
+#include <limits.h>
+
+using namespace std;
+
+double getave(int * arr, int len);
+int getmean(int * arr, int len);
+int getmode(int * arr, int len);
+int getrange(int * arr, int len);
+
+int main() {
+	double ave, mean, mode, range = 0;
+	int N;
+
+	cout << "enter length of list : ";
+	cin >> N;
+
+	int * arr = new int[N];
+
+	for(int i = 0; i < N; i++){
+		cout << "enter " << i+1 << "th value : ";
+		cin >> arr[i];
+	}
+	ave = getave(arr, N);
+	mean = getmean(arr, N);
+	mode = getmode(arr, N);
+	range = getrange(arr, N);
+
+	cout << "ave : " << ave << endl;
+	cout << "mean : " << mean << endl;
+	cout << "mode : " << mode << endl;
+	cout << "range : " << range << endl;
+
+	delete[] arr;
+	return 0;
+}
+
+double getave(int * arr, int len) {
+	double result = 0;
+	for(int i = 0; i < len; i++){
+		result += arr[i];
+	}
+	result /= (double)len;
+	return result;
+}
+
+int getmean(int * arr, int len) {
+	// sort in ascending order
+	sort(arr, arr+len);	
+
+	// find the middle value from sorted list
+	int i = len/2;
+	return arr[i];
+}
+
+int getmode(int * arr, int len) {
+	// traverse through array
+	// have counting variable for each value
+
+	int cntlen = arr[len-1]+1;
+	int * cnt = new int[cntlen];
+	int * modes = new int[cntlen];
+	int mode = 0;	
+	// initialize
+	for(int i = 0; i < cntlen; i++) {
+		cnt[i] = 0;
+		modes[i] = 0;
+	}
+
+	// count
+	for(int i = 0; i < len; i++) {
+		cnt[arr[i]]++;
+	}
+
+	/* test print
+	   for(int i = 0; i < cntlen; i++) {
+	   cout << "cnt [" << i << "] : " << cnt[i] << endl;
+	   }
+	 */	
+
+	// compare maximum counting variable and return that value
+	int max =  INT_MIN;
+	for(int i = 0; i < cntlen; i++) {
+		if(cnt[i] >  max) max = cnt[i];
+		if(cnt[i] == max) modes[i] = i;
+	}
+	sort(modes, modes+cntlen, greater<int>());
+
+	/* test print
+	   for(int i = 0; i < cntlen; i++) {
+	   cout << "modes[" << i << "] : " << modes[i] << endl;
+	   }
+	 */
+
+	mode = modes[1];
+	return mode;
+}
+
+int getrange(int * arr, int len) {
+	// it's already sorted
+	// max - min
+	return arr[len-1] - arr[0];
+}
diff --git a/problems/2581/21500426.cpp b/problems/2581/21500426.cpp
new file mode 100644
index 0000000..c1e8af2
--- /dev/null
+++ b/problems/2581/21500426.cpp
@@ -0,0 +1,12 @@
+#include <iostream>
+
+int main () {
+
+
+
+
+
+
+
+	return 0;
+}