From 9996e2871eb6dbc2b8e18967b2864461bcc6436a Mon Sep 17 00:00:00 2001
From: kkunkka <kkunkka@zohomail.com>
Date: Mon, 7 Jul 2025 16:00:15 +0800
Subject: [PATCH] kk

---
 .../java/com/dota/bit/_2857/Solution.java     | 22 ++++++++++++
 .../java/com/dota/bit/_3153/Solution.java     | 36 +++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 src/main/java/com/dota/bit/_2857/Solution.java
 create mode 100644 src/main/java/com/dota/bit/_3153/Solution.java

diff --git a/src/main/java/com/dota/bit/_2857/Solution.java b/src/main/java/com/dota/bit/_2857/Solution.java
new file mode 100644
index 0000000..dcdf7b7
--- /dev/null
+++ b/src/main/java/com/dota/bit/_2857/Solution.java
@@ -0,0 +1,22 @@
+package com.dota.bit._2857;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+class Solution {
+	public int countPairs(List<List<Integer>> coordinates, int k) {
+		int res = 0;
+		var map = new HashMap<Long, Integer>();
+		for (List<Integer> coordinate : coordinates) {
+			var x = coordinate.get(0);
+			var y = coordinate.get(1);
+
+			for (int i = 0; i <= k; i++) {
+				res += map.getOrDefault((x ^ i) * 2000000L + (y ^ (k - i)), 0);
+			}
+			map.merge(x * 2000000L + y, 1, Integer::sum);
+		}
+		return res;
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/com/dota/bit/_3153/Solution.java b/src/main/java/com/dota/bit/_3153/Solution.java
new file mode 100644
index 0000000..e08a976
--- /dev/null
+++ b/src/main/java/com/dota/bit/_3153/Solution.java
@@ -0,0 +1,36 @@
+package com.dota.bit._3153;
+
+import java.util.HashMap;
+import java.util.Map;
+
+class Solution {
+	public static void main(String[] args) {
+		new Solution().sumDigitDifferences(new int[]{13,23,12});
+	}
+	public long sumDigitDifferences(int[] nums) {
+		long res = 0;
+		int t = nums[0];
+		int len = 0;
+		while (t > 0) {
+			len++;
+			t /= 10;
+		}
+
+		Map<Integer, Integer>[] dp = new Map[len];
+		for (int i = 0; i < dp.length; i++) {
+			dp[i] = new HashMap<>();
+		}
+
+		int sum=0;
+		for (int num : nums) {
+			for (int i = 0; i < len; i++) {
+				t = num % 10;
+				res = res + (sum - dp[i].getOrDefault(t, 0));
+				dp[i].put(t, 1 + dp[i].getOrDefault(t, 0));
+				num /= 10;
+			}
+			sum++;
+		}
+		return res;
+	}
+}
\ No newline at end of file