From 25aa806dd159bfc8fadcc463b8e0167400e115b4 Mon Sep 17 00:00:00 2001
From: Ukj0ng <90972240+Ukj0ng@users.noreply.github.com>
Date: Mon, 15 Dec 2025 11:22:29 +0900
Subject: [PATCH] =?UTF-8?q?[20251215]=20BOJ=20/=20G3=20/=20=EB=B2=8C?=
 =?UTF-8?q?=EB=A0=88=EC=BB=B7=20/=20=ED=95=9C=EC=A2=85=EC=9A=B1?=
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---
 ...3 \353\262\214\353\240\210\354\273\267.md" | 79 +++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 "Ukj0ng/202512/15 BOJ G3 \353\262\214\353\240\210\354\273\267.md"

diff --git "a/Ukj0ng/202512/15 BOJ G3 \353\262\214\353\240\210\354\273\267.md" "b/Ukj0ng/202512/15 BOJ G3 \353\262\214\353\240\210\354\273\267.md"
new file mode 100644
index 00000000..05b7fcbe
--- /dev/null
+++ "b/Ukj0ng/202512/15 BOJ G3 \353\262\214\353\240\210\354\273\267.md"	
@@ -0,0 +1,79 @@
+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static int[] arr;
+    private static long[] sum;
+    private static int N;
+    private static long answer;
+
+    public static void main(String[] args) throws IOException {
+        init();
+        for (int i = 0; i < N-1; i++) {
+            int max = upperBound(i);
+            int min = lowerBound(i);
+
+            if (max != -1 && min != -1 && min <= max) {
+                answer += (max-min+1);
+            }
+        }
+
+        bw.write(answer + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        N = Integer.parseInt(br.readLine());
+        arr = new int[N];
+        sum = new long[N];
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < N; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+            if (i == 0) sum[i] = arr[i];
+            else sum[i] = sum[i-1]+arr[i];
+        }
+    }
+
+    private static int upperBound(int head) {
+        int left = head+1;
+        int right = N-2;
+        int result = -1;
+
+        while (left <= right) {
+            int mid = left + (right-left)/2;
+
+            if (sum[head] < (sum[N-1]-sum[mid])) {
+                result = mid;
+                left = mid+1;
+            } else {
+                right = mid-1;
+            }
+        }
+        return result;
+    }
+
+    private static int lowerBound(int head) {
+        int left = head+1;
+        int right = N-2;
+        int result = -1;
+
+        while (left <= right) {
+            int mid = left + (right-left)/2;
+
+            if ((sum[N-1]-sum[mid]) < (sum[mid]-sum[head])) {
+                result = mid;
+                right = mid-1;
+            } else {
+                left = mid+1;
+            }
+        }
+        return result;
+    }
+}
+```