update README.md

devOTTO · devOTTO · commit 8a8aeca57a10 · 2019-05-23T21:46:09.000+09:00
diff --git a/README.md b/README.md
@@ -121,4 +121,5 @@ Personal Solution of Algorithm Probs
 - [2108](https://www.acmicpc.net/problem/2108) : 통계학 = [풀이](https://github.com/devOTTO/Algorithm-Study/blob/master/baekjoon/2108.cpp)
 - [1427](https://www.acmicpc.net/problem/1427) : 소트인사이드 = [풀이](https://github.com/devOTTO/Algorithm-Study/blob/master/baekjoon/1427.cpp)
 #### [10.소수 구하기](https://www.acmicpc.net/step/10)
-- [1978](https://www.acmicpc.net/problem/1978) : 소수 찾기 = [풀이](https://github.com/devOTTO/Algorithm-Study/blob/master/baekjoon/1978.cpp)
+- [1978](https://www.acmicpc.net/problem/1978) : 소수 찾기 = [풀이](https://github.com/devOTTO/Algorithm-Study/blob/master/baekjoon/1978.cpp)
+- [2581](https://www.acmicpc.net/problem/2581) : 소수 = [풀이](https://github.com/devOTTO/Algorithm-Study/blob/master/baekjoon/2581.cpp)
diff --git a/baekjoon/2581.cpp b/baekjoon/2581.cpp
@@ -0,0 +1,49 @@
+//
+// Created by 융미 on 2019-05-23.
+//*2581 소수
+#include <iostream>
+using namespace std;
+
+int m, n;
+
+bool isSosu(int num){
+
+    if(num == 1) return 0;
+    if(num == 2) return 1;
+    for(int i = 2; i<num; i++)
+    {
+        if(num%i== 0)
+            return 0;
+    }
+    return 1;
+}
+
+int main() {
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    cin >> m >> n;
+
+    int sum = 0;
+    int min = 10001;
+    for(int i = m; i<= n; i++)
+    {
+        if(isSosu(i))
+        {
+            sum+= i;
+            if(min > i) min = i;
+        }
+    }
+
+    if(sum == 0)
+    {
+        cout << -1;
+    }
+    else {
+        cout << sum << '\n';
+        cout << min << '\n';
+    }
+    return 0;
+}
+
+
