Add problem 3162: Find the Number of Good Pairs I

Author: EFanZh

src/lib.rs

@@ -2114,6 +2114,7 @@ pub mod problem_3153_sum_of_digit_differences_of_all_pairs;
 pub mod problem_3158_find_the_xor_of_numbers_which_appear_twice;
 pub mod problem_3159_find_occurrences_of_an_element_in_an_array;
 pub mod problem_3160_find_the_number_of_distinct_colors_among_the_balls;
+pub mod problem_3162_find_the_number_of_good_pairs_i;
 pub mod problem_3164_find_the_number_of_good_pairs_ii;
 pub mod problem_3350_adjacent_increasing_subarrays_detection_ii;
 

src/problem_3162_find_the_number_of_good_pairs_i/hash_map.rs

@@ -0,0 +1,59 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+use std::collections::HashMap;
+use std::collections::hash_map::Entry;
+
+impl Solution {
+    pub fn number_of_pairs(nums1: Vec<i32>, nums2: Vec<i32>, k: i32) -> i64 {
+        let nums1 = nums1.into_iter().map(i32::cast_unsigned).collect::<Vec<_>>();
+        let nums2 = nums2.into_iter().map(i32::cast_unsigned).collect::<Vec<_>>();
+        let k = k.cast_unsigned();
+        let max = nums1.iter().copied().max().unwrap_or(0);
+        let mut counts_1 = vec![0_u32; max as usize + 1].into_boxed_slice();
+
+        for num in nums1 {
+            counts_1[num as usize] += 1;
+        }
+
+        let mut counts_2 = HashMap::new();
+
+        for num in nums2 {
+            match counts_2.entry(num * k) {
+                Entry::Occupied(occupied_entry) => *occupied_entry.into_mut() += 1,
+                Entry::Vacant(vacant_entry) => {
+                    vacant_entry.insert(1_u32);
+                }
+            }
+        }
+
+        counts_2
+            .into_iter()
+            .filter_map(|(factor, count)| {
+                let factor = factor as usize;
+
+                counts_1
+                    .get(factor..)
+                    .map(|range| range.iter().step_by(factor).copied().map(u64::from).sum::<u64>() * u64::from(count))
+            })
+            .sum::<u64>()
+            .cast_signed()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn number_of_pairs(nums1: Vec<i32>, nums2: Vec<i32>, k: i32) -> i64 {
+        Self::number_of_pairs(nums1, nums2, k)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_3162_find_the_number_of_good_pairs_i/mod.rs

@@ -0,0 +1,22 @@
+pub mod hash_map;
+
+pub trait Solution {
+    fn number_of_pairs(nums1: Vec<i32>, nums2: Vec<i32>, k: i32) -> i64;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            ((&[1, 3, 4] as &[_], &[1, 3, 4] as &[_], 1), 5),
+            ((&[1, 2, 4, 12], &[2, 4], 3), 2),
+            ((&[1], &[8], 1), 0),
+        ];
+
+        for ((nums1, nums2, k), expected) in test_cases {
+            assert_eq!(S::number_of_pairs(nums1.to_vec(), nums2.to_vec(), k), expected);
+        }
+    }
+}