Create 0567-permutation-in-string.rs

Author: nirajvenkat

rust/0567-permutation-in-string.rs

@@ -0,0 +1,45 @@
+impl Solution {
+    pub fn check_inclusion(s1: String, s2: String) -> bool {
+        if s1.len() > s2.len() {
+            return false;
+        }
+
+        let (mut s1_cnt, mut s2_cnt) = ([0; 26], [0; 26]);
+        for i in 0..s1.len() {
+            s1_cnt[s1.chars().nth(i).unwrap() as usize - 'a' as usize] += 1;
+            s2_cnt[s2.chars().nth(i).unwrap() as usize - 'a' as usize] += 1;
+        }
+
+        let mut matches = 0;
+        for i in 0..26 {
+            matches = if s1_cnt[i] == s2_cnt[i] { matches + 1 } else { matches };
+        }
+
+        let mut l = 0;
+        for r in s1.len()..s2.len() {
+            if matches == 26 {
+                return true;
+            }
+
+            let mut index = s2.chars().nth(r).unwrap() as usize - 'a' as usize;
+            s2_cnt[index] += 1;
+            if s1_cnt[index] == s2_cnt[index] {
+                matches += 1;
+            } else if s1_cnt[index] + 1 == s2_cnt[index]{
+                matches -= 1;
+            }
+
+            index = s2.chars().nth(l).unwrap() as usize - 'a' as usize;
+            s2_cnt[index] -= 1;
+            if s1_cnt[index] == s2_cnt[index] {
+                matches += 1;
+            } else if s1_cnt[index] - 1 == s2_cnt[index]{
+                matches -= 1;
+            }
+
+            l += 1;
+        }
+
+        matches == 26
+    }
+}