Algorithm

Algorithm/Maths/P1102 A-B数对/P1102 A-B 数对 unordered_set不过 有重复.cpp

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+#include <unordered_set>
+#include <iostream>
+using namespace std;
+int main(){
+	unordered_multiset<int> s;
+	int n, m;
+	cin >> n >> m;
+	int tmp;
+	for(int i = 0; i < n; i++){
+		cin >> tmp;
+		s.emplace(tmp);
+	}
+	int js = 0;
+	for(auto it = s.begin(); it != s.end(); it++){
+		js += s.count(*it - m);
+	} 
+	cout << js << endl;
+	return 0;
+}