feat: add rust solution to lc problem: No.3169 (#4560)

No.3169.Count Days Without Meetings

Author: yanglbme

solution/3100-3199/3169.Count Days Without Meetings/README.md

@@ -183,6 +183,29 @@ function countDays(days: number, meetings: number[][]): number {
 }
 ```
 
+#### Rust
+
+```rust
+impl Solution {
+    pub fn count_days(days: i32, mut meetings: Vec<Vec<i32>>) -> i32 {
+        meetings.sort_by_key(|m| m[0]);
+        let mut ans = 0;
+        let mut last = 0;
+
+        for e in meetings {
+            let st = e[0];
+            let ed = e[1];
+            if last < st {
+                ans += st - last - 1;
+            }
+            last = last.max(ed);
+        }
+
+        ans + (days - last)
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/3100-3199/3169.Count Days Without Meetings/README_EN.md

@@ -181,6 +181,29 @@ function countDays(days: number, meetings: number[][]): number {
 }
 ```
 
+#### Rust
+
+```rust
+impl Solution {
+    pub fn count_days(days: i32, mut meetings: Vec<Vec<i32>>) -> i32 {
+        meetings.sort_by_key(|m| m[0]);
+        let mut ans = 0;
+        let mut last = 0;
+
+        for e in meetings {
+            let st = e[0];
+            let ed = e[1];
+            if last < st {
+                ans += st - last - 1;
+            }
+            last = last.max(ed);
+        }
+
+        ans + (days - last)
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/3100-3199/3169.Count Days Without Meetings/Solution.rs

@@ -0,0 +1,18 @@
+impl Solution {
+    pub fn count_days(days: i32, mut meetings: Vec<Vec<i32>>) -> i32 {
+        meetings.sort_by_key(|m| m[0]);
+        let mut ans = 0;
+        let mut last = 0;
+
+        for e in meetings {
+            let st = e[0];
+            let ed = e[1];
+            if last < st {
+                ans += st - last - 1;
+            }
+            last = last.max(ed);
+        }
+
+        ans + (days - last)
+    }
+}