[정수] week38

src/이정수/week38/BJ_7453_합이0인네정수.java

@@ -0,0 +1,91 @@
+package week38;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.StringTokenizer;
+
+/**
+ * ����: ���� 0�� �� ���� ��ũ: https://www.acmicpc.net/problem/7453
+ * 
+ * Ǯ��:
+ * 
+ * 
+ * �ð����⵵:
+ * 
+ * 
+ * Ǯ�̿� �ɸ� �ð�:
+ * 
+ *
+ */
+public class BJ_7453_����0����� {
+
+	static long[] CD;
+
+	public static void main(String[] args) throws NumberFormatException, IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st;
+
+		int n = Integer.parseInt(br.readLine());
+
+		long[] A = new long[n];
+		long[] B = new long[n];
+		long[] C = new long[n];
+		long[] D = new long[n];
+		long[] AB = new long[n * n];
+		CD = new long[n * n];
+
+		for (int i = 0; i < n; ++i) {
+			st = new StringTokenizer(br.readLine());
+			A[i] = Long.parseLong(st.nextToken());
+			B[i] = Long.parseLong(st.nextToken());
+			C[i] = Long.parseLong(st.nextToken());
+			D[i] = Long.parseLong(st.nextToken());
+		}
+
+		int idx = 0;
+		for (int i = 0; i < n; ++i) {
+			for (int j = 0; j < n; ++j) {
+				AB[idx] = A[i] + B[j];
+				CD[idx++] = C[i] + D[j];
+			}
+		}
+
+		Arrays.sort(AB);
+		Arrays.sort(CD);
+
+		long cnt = 0;
+		for (int i = 0; i < AB.length; ++i) {
+			cnt += getUpperBound(0, CD.length, -AB[i]) - getLowerBound(0, CD.length, -AB[i]);
+		}
+
+		System.out.println(cnt);
+	}
+
+	private static int getUpperBound(int left, int right, long target) {
+		while (left < right) {
+			int mid = (left + right) / 2;
+			if (CD[mid] <= target) {
+				left = mid + 1;
+			} else {
+				right = mid;
+			}
+		}
+		return right;
+	}
+
+	private static int getLowerBound(int left, int right, long target) {
+		while (left < right) {
+			int mid = (left + right) / 2;
+			if (CD[mid] < target) {
+				left = mid + 1;
+			} else {
+				right = mid;
+			}
+		}
+		return right;
+	}
+
+}