ABC 252, in process of making c, got idea but got sidetracked

atcoder/beginner_contests/252/b.cpp

@@ -0,0 +1,44 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+
+int main(){
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    int n, k;
+    cin >> n >> k;
+
+    set<int> tasty_foods;
+    int tastiest = 0;
+
+    for(int i = 0; i < n; ++i){
+        int a;
+        cin >> a;
+        
+        if(a > tastiest){
+            tasty_foods.clear();
+            tastiest = a;
+            tasty_foods.insert(i+1);
+        } else if(a == tastiest){
+            tasty_foods.insert(i+1);
+        }
+    }
+
+    for(int i = 0; i < k; ++i){
+        int b;
+        cin >> b;
+
+        if(tasty_foods.count(b)){
+            cout << "Yes" << endl;
+            return 0;
+        }
+    }
+
+    cout << "No" << endl;
+
+    cout << flush;
+
+    return 0;
+}