practice leetcode - longest consecutive sequence

src/practice/leetcode/longest_consecutive_sequence/Cargo.toml

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+[package]
+name = "longest_consecutive_sequence"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

src/practice/leetcode/longest_consecutive_sequence/src/main.rs

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+// https://leetcode.com/problems/longest-consecutive-sequence/
+
+struct Solution;
+
+impl Solution {
+    pub fn longest_consecutive(nums: Vec<i32>) -> i32 {
+        use std::collections::HashMap;
+        let mut cnt: HashMap<i32, i32> = HashMap::new();
+        let mut visited: HashMap<i32, bool> = HashMap::new();
+        let mut mark: HashMap<i32, bool> = HashMap::new();
+        for &n in &nums {
+            mark.insert(n, true);
+        }
+        let mut ans = 0;
+        for &n in &nums {
+            if *visited.get(&n).unwrap_or(&false) {
+                continue;
+            }
+            let mut itr = n;
+            let mut nbr = 0;
+            while !visited.get(&itr).unwrap_or(&false) && *mark.get(&itr).unwrap_or(&false) {
+                nbr += 1;
+                visited.insert(itr, true);
+                itr += 1;
+            }
+            cnt.insert(n, nbr);
+            if let Some(&next_cnt) = cnt.get(&itr) {
+                *cnt.get_mut(&n).unwrap() += next_cnt;
+            }
+            ans = ans.max(*cnt.get(&n).unwrap());
+        }
+        ans
+    }
+}
+
+fn main() {
+    let nums = vec![100, 4, 200, 1, 3, 2];
+    let result = Solution::longest_consecutive(nums);
+    println!("{result}")
+}