leetcode: Add 1534

src/leetcode/1534.count-good-triplets/Cargo.toml

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+[package]
+name = "lc-1534-count-good-triplets"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]

src/leetcode/1534.count-good-triplets/index.md

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+
+# 
+
+[问题描述](../problems/)

src/leetcode/1534.count-good-triplets/src/main.rs

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+// 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.
+
+// Bruteforce
+pub fn count_good_triplets1(arr: Vec<i32>, a: i32, b: i32, c: i32) -> i32 {
+    let len: usize = arr.len();
+    let mut count: i32 = 0;
+
+    // 三层嵌套循环
+    for i in 0..(len - 2) {
+        for j in (i + 1)..(len - 1) {
+            for k in (j + 1)..len {
+                if (arr[i] - arr[j]).abs() <= a
+                    && (arr[j] - arr[k]).abs() <= b
+                    && (arr[i] - arr[k]).abs() <= c
+                {
+                    count += 1;
+                }
+            }
+        }
+    }
+    count
+}
+
+// 优化循环
+pub fn count_good_triplets2(arr: Vec<i32>, a: i32, b: i32, c: i32) -> i32 {
+    let len: usize = arr.len();
+    let mut count: i32 = 0;
+
+    // 三层嵌套循环
+    for i in 0..(len - 2) {
+        for j in (i + 1)..(len - 1) {
+            if (arr[i] - arr[j]).abs() > a {
+                continue;
+            }
+
+            for k in (j + 1)..len {
+                if (arr[j] - arr[k]).abs() <= b && (arr[i] - arr[k]).abs() <= c {
+                    count += 1;
+                }
+            }
+        }
+    }
+    count
+}
+
+pub type SolutionFn = fn(Vec<i32>, i32, i32, i32) -> i32;
+
+fn check_solution(func: SolutionFn) {
+    let arr = vec![3, 0, 1, 1, 9, 7];
+    assert_eq!(func(arr, 7, 2, 3), 4);
+
+    let arr = vec![1, 1, 2, 2, 3];
+    assert_eq!(func(arr, 0, 0, 1), 0);
+}
+
+fn main() {
+    check_solution(count_good_triplets1);
+    check_solution(count_good_triplets2);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{check_solution, count_good_triplets1, count_good_triplets2};
+
+    #[test]
+    fn test_count_good_triplets1() {
+        check_solution(count_good_triplets1);
+    }
+
+    #[test]
+    fn test_count_good_triplets2() {
+        check_solution(count_good_triplets2);
+    }
+}