leetcode: Add 0463

src/SUMMARY.md

@@ -302,6 +302,7 @@
         - [0374. 猜数字大小 Guess Number Higher or Lower](leetcode/0374.guess-number-higher-or-lower/index.md)
         - [0394. 字符串解码 Decode String](leetcode/0394.decode-string/index.md)
     - [0401-0500](leetcode/by-id/0401-0500.md)
+        - [0463. 岛屿的周长 Island Perimeter](leetcode/0463.island-perimeter/index.md)
         - [0468. 验证IP地址 Validate IP Address](leetcode/0468.validate-ip-address/index.md)
         - [0485. 最大连续1的个数 Max Consecutive Ones](leetcode/0485.max-consecutive-ones/index.md)
         - [0496. 下一个更大元素 I Next Greater Element I](leetcode/0496.next-greater-element-i/index.md)

src/leetcode/0463.island-perimeter/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "lc-0463-island-perimeter"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]

src/leetcode/0463.island-perimeter/index.md

@@ -0,0 +1,4 @@
+
+# 0463. 岛屿的周长 Island Perimeter
+
+[问题描述](https://leetcode.com/problems/island-perimeter)

src/leetcode/0463.island-perimeter/src/main.rs

@@ -0,0 +1,87 @@
+// Copyright (c) 2024 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by General Public License that can be found
+// in the LICENSE file.
+
+// Brute force
+// 时间复杂度 O(m * n)
+pub fn island_perimeter1(grid: Vec<Vec<i32>>) -> i32 {
+    // 一个岛屿有多个方格组成,  一个方格有四个边.
+    // 对于任意一个边, 当与组成岛屿的另一个方格相邻时, 在计算岛的周长时,
+    // 就不需要计算这个边;
+    // 当不与组成岛屿的另一个方格相邻时, 在计算周长时, 就要算上这个边.
+    // 一个岛域的周长, 就是这些方格的边的总和.
+    // 遍历所有方格, 检查它是不是岛屿的一部分.
+    // 如果是, 就检查它的四个边, 是否能作为岛域周长的一部分.
+
+    const IS_ISLAND: i32 = 1;
+    const IS_NOT_ISLAND: i32 = 0;
+    let rows = grid.len();
+    assert!((1..=100).contains(&rows));
+    let columns = grid[0].len();
+    assert!((1..=100).contains(&columns));
+    let rows_i32 = rows as i32;
+    let columns_i32 = columns as i32;
+    // 可能的四个方向.
+    let directions = [(0_i32, -1_i32), (-1, 0), (1, 0), (0, 1)];
+
+    let mut sum = 0;
+    for row in 0..rows {
+        for column in 0..columns {
+            if grid[row][column] == IS_ISLAND {
+                // 尝试四个边
+                for dir in directions {
+                    let row1 = row as i32 + dir.0;
+                    let column1 = column as i32 + dir.1;
+                    if 0 <= row1 && row1 < rows_i32 && 0 <= column1 && column1 < columns_i32 {
+                        // 如果相邻的方格是 grid 内部
+                        let row1 = row1 as usize;
+                        let column1 = column1 as usize;
+
+                        // 并且它不是岛屿的一部分.
+                        if grid[row1][column1] == IS_NOT_ISLAND {
+                            sum += 1;
+                        }
+                    } else {
+                        // 如果相邻的方格不是在 grid 内部, 说明这个边可以作为岛屿周长的一部分.
+                        sum += 1;
+                    }
+                }
+            }
+        }
+    }
+
+    // 返回结果
+    sum
+}
+
+pub type SolutionFn = fn(Vec<Vec<i32>>) -> i32;
+
+fn check_solution(func: SolutionFn) {
+    let grid = vec![
+        vec![0, 1, 0, 0],
+        vec![1, 1, 1, 0],
+        vec![0, 1, 0, 0],
+        vec![1, 1, 0, 0],
+    ];
+    assert_eq!(func(grid), 16);
+
+    let grid = vec![vec![1]];
+    assert_eq!(func(grid), 4);
+
+    let grid = vec![vec![1, 0]];
+    assert_eq!(func(grid), 4);
+}
+
+fn main() {
+    check_solution(island_perimeter1);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{check_solution, island_perimeter1};
+
+    #[test]
+    fn test_island_perimeter1() {
+        check_solution(island_perimeter1);
+    }
+}

src/leetcode/tags/array/matrix.md

@@ -1,7 +1,8 @@
 # 矩阵 Matrix
 
 ## 简单
+1. [0463. 岛屿的周长 Island Perimeter](../../0463.island-perimeter/index.md)
 
 ## 中等
 
-## 困难
+## 困难