feat: solve 10816, 숫자 카드2bsearch, s4, 40m)

junji/binary_search/10816.cpp

@@ -0,0 +1,77 @@
+#include <iostream>
+#include <stack>
+#include <queue>
+#include <vector>
+#include <utility>
+#include <algorithm>
+#include <string.h>
+using namespace std;
+
+int N;
+int S[500000];
+int M;
+
+int	find_end_idx(int number)
+{
+	int	left = 0;
+	int right = N;
+
+	while (left < right)
+	{
+		int mid = (left + right) / 2;
+		if (S[mid] <= number)
+		{
+			left = mid + 1;
+		}
+		else
+		{
+			right = mid;
+		}
+	}
+	return (left);
+}
+
+int	find_start_idx(int number)
+{
+	int left = 0;
+	int right = N; // N - 1이 아니다
+
+	while (left < right) // = 등호가 없다!
+	{
+		int mid = (left + right) / 2;
+		if (S[mid] < number) // 10이 들어갈 수 있는 가장 왼쪽의 위치는 mid이하라는 거
+		{
+			left = mid + 1;
+		}
+		else
+		{
+			right = mid;
+		}
+	}
+	return (left);
+}
+
+void	get_input()
+{
+	cin >> N;
+	for (int i = 0; i < N; ++i) 
+	{
+		cin >> S[i];
+	}
+	cin >> M;
+	sort(S, S + N);
+	for (int i = 0; i < M; ++i) 
+	{
+		int number;
+		cin >> number;
+		cout << find_end_idx(number) - find_start_idx(number) << ' ';
+	}
+}
+
+int main(void)
+{
+	ios::sync_with_stdio(false);
+	cin.tie(NULL);
+
+	get_input();
+}