一刷1864

Author: diguage

README.adoc

@@ -13074,12 +13074,12 @@ TIP: **公众号的微信号是: `jikerizhi`**。__因为众所周知的原因
 //|Easy
 //|
 
-//|{counter:codes}
-//|{leetcode_base_url}/minimum-number-of-swaps-to-make-the-binary-string-alternating/[1864. Minimum Number of Swaps to Make the Binary String Alternating^]
-//|{source_base_url}/_1864_MinimumNumberOfSwapsToMakeTheBinaryStringAlternating.java[Java]
-//|{doc_base_url}/1864-minimum-number-of-swaps-to-make-the-binary-string-alternating.adoc[题解]
-//|Medium
-//|
+|{counter:codes}
+|{leetcode_base_url}/minimum-number-of-swaps-to-make-the-binary-string-alternating/[1864. Minimum Number of Swaps to Make the Binary String Alternating^]
+|{source_base_url}/_1864_MinimumNumberOfSwapsToMakeTheBinaryStringAlternating.java[Java]
+|{doc_base_url}/1864-minimum-number-of-swaps-to-make-the-binary-string-alternating.adoc[题解]
+|Medium
+|
 
 //|{counter:codes}
 //|{leetcode_base_url}/finding-pairs-with-a-certain-sum/[1865. Finding Pairs With a Certain Sum^]

docs/0000-00-note.adoc

@@ -249,6 +249,7 @@ image::images/quick-sort-01.gif[{image_attr}]
 
 == 参考资料
 
+. https://leetcode.cn/circle/discuss/RvFUtj/[如何科学刷题？ - 按照难度系数刷题^]
 . https://www.designgurus.io/course/grokking-the-coding-interview[Grokking the Coding Interview Patterns^]
 . https://leetcode.ca/all/1650.html[Leetcode 1650. Lowest Common Ancestor of a Binary Tree III^] -- 会员题目可以在这里查找。
 . https://github.com/doocs/leetcode[doocs/leetcode: 🔥LeetCode solutions in any programming language | 多种编程语言实现 LeetCode、《剑指 Offer（第 2 版）》、《程序员面试金典（第 6 版）》题解^] -- 也可以在这里找题目

docs/1864-minimum-number-of-swaps-to-make-the-binary-string-alternating.adoc

@@ -41,14 +41,15 @@ The string is now alternating.
 *Constraints:*
 
 
-* `1 <= s.length <= 1000`
+* `1 \<= s.length \<= 1000`
 * `s[i]` is either `'0'` or `'1'`.
 
 
 
 
 == 思路分析
 
+如果是交替出现，那么只有 `010...` 或者 `101...` 这两种类型，统计各个比特位不正确的位数再除以 2 即可。（交换一次，可以解决两个不正确比特位）。
 
 [[src-1864]]
 [tabs]
@@ -75,4 +76,5 @@ include::{sourcedir}/_1864_MinimumNumberOfSwapsToMakeTheBinaryStringAlternating.
 
 == 参考资料
 
+. https://leetcode.cn/problems/minimum-number-of-swaps-to-make-the-binary-string-alternating/solutions/779087/minimum-number-of-swaps-to-make-the-bina-z0qy/[1864. 构成交替字符串需要的最小交换次数 - 官方题解^]
 

docs/index.adoc

@@ -3802,7 +3802,7 @@ include::1823-find-the-winner-of-the-circular-game.adoc[leveloffset=+1]
 
 // include::1863-sum-of-all-subset-xor-totals.adoc[leveloffset=+1]
 
-// include::1864-minimum-number-of-swaps-to-make-the-binary-string-alternating.adoc[leveloffset=+1]
+include::1864-minimum-number-of-swaps-to-make-the-binary-string-alternating.adoc[leveloffset=+1]
 
 // include::1865-finding-pairs-with-a-certain-sum.adoc[leveloffset=+1]
 

logbook/202406.adoc

@@ -853,6 +853,11 @@
 |{doc_base_url}/0079-word-search.adoc[题解]
 |✅ 回溯
 
+|{counter:codes}
+|{leetcode_base_url}/minimum-number-of-swaps-to-make-the-binary-string-alternating/[1864. Minimum Number of Swaps to Make the Binary String Alternating^]
+|{doc_base_url}/1864-minimum-number-of-swaps-to-make-the-binary-string-alternating.adoc[题解]
+|❌ 贪心算法
+
 |===
 
 截止目前，本轮练习一共完成 {codes} 道题。

src/main/java/com/diguage/algo/leetcode/_1864_MinimumNumberOfSwapsToMakeTheBinaryStringAlternating.java

@@ -0,0 +1,55 @@
+package com.diguage.algo.leetcode;
+
+public class _1864_MinimumNumberOfSwapsToMakeTheBinaryStringAlternating {
+  // tag::answer[]
+
+  /**
+   * @author D瓜哥 · https://www.diguage.com
+   * @since 2024-09-24 16:26:07
+   */
+  public int minSwaps(String s) {
+    int[] bits = bits(s);
+    int b0 = bits[0];
+    int b1 = bits[1];
+    int n = s.length();
+    int result = Integer.MAX_VALUE;
+    // 1010...
+    if (b0 == n / 2 && b1 == (n + 1) / 2) {
+      int diff = 0;
+      for (int i = 0; i < n; i++) {
+        if (s.charAt(i) - '0' == i % 2) {
+          diff++;
+        }
+      }
+      result = Math.min(result, diff / 2);
+    }
+    // 0101...
+    if (b0 == (n + 1) / 2 && b1 == n / 2) {
+      int diff = 0;
+      for (int i = 0; i < n; i++) {
+        if (s.charAt(i) - '0' != i % 2) {
+          diff++;
+        }
+      }
+      result = Math.min(result, diff / 2);
+    }
+    return result != Integer.MAX_VALUE ? result : -1;
+  }
+
+  private int[] bits(String s) {
+    int b0 = 0;
+    for (int i = 0; i < s.length(); i++) {
+      if (s.charAt(i) == '0') {
+        b0++;
+      }
+    }
+    return new int[]{b0, s.length() - b0};
+  }
+
+  // end::answer[]
+
+  public static void main(String[] args) {
+    new _1864_MinimumNumberOfSwapsToMakeTheBinaryStringAlternating()
+      .minSwaps("1110");
+  }
+}