Create: 2001-number-of-pairs-of-interchangeable-rectangles.rs

Author: MartinLwx

rust/2001-number-of-pairs-of-interchangeable-rectangles.rs

@@ -0,0 +1,36 @@
+use std::collections::HashMap;
+impl Solution {
+    pub fn compute_gcd(mut a: i32, mut b: i32) -> i32 {
+        while a > 0 && b > 0 {
+            if a > b {
+                a %= b;
+            } else {
+                b %= a;
+            }
+        }
+        if a == 0 {
+            b
+        } else {
+            a
+        }
+    }
+    pub fn interchangeable_rectangles(rectangles: Vec<Vec<i32>>) -> i64 {
+        rectangles
+            .into_iter()
+            .map(|v| {
+                let gcd = Solution::compute_gcd(v[0], v[1]);
+                (v[0] / gcd, v[1] / gcd)
+            })
+            .fold(HashMap::new(), |mut dict, t| {
+                dict.entry(t).and_modify(|cnt| *cnt += 1).or_insert(1);
+                dict
+            })
+            .into_iter()
+            .filter(|(_, v)| *v > 1)
+            .map(|(_, v)| v)
+            .fold(0, |mut cnt, v| {
+                cnt += v * (v - 1) / 2;
+                cnt
+            })
+    }
+}