p3306

Author: ian-hon

src/main.rs

@@ -1,5 +1,5 @@
-mod p3208;
+mod p3306;
 
 pub fn main() {
-    p3208::run();
+    p3306::run();
 }

src/p3306.rs

@@ -0,0 +1,76 @@
+use std::collections::HashMap;
+
+pub fn run() {
+    for i in [
+        ("aeioqq", 1),
+        ("aeiou", 0),
+        ("ieaouqqieaouqq", 1)
+    ] {
+        println!("{}", count_of_substrings(i.0.to_string(), i.1));
+    }
+}
+
+pub fn count_of_substrings(word: String, k: i32) -> i64 {
+    let chars = word.chars().collect::<Vec<char>>();
+
+    at_least(&chars, k) - at_least(&chars, k + 1)
+}
+
+pub fn at_least(chars: &Vec<char>, k: i32) -> i64 {
+    let is_vowel = |x: char| (x == 'a') || (x == 'e') || (x == 'i') || (x == 'o') || (x == 'u');
+
+    let l = chars.len();
+
+    let mut map: HashMap<char, i64> = HashMap::new();
+    let mut consonant_count = 0;
+
+    let mut vowel_reached = false;
+
+    let mut result = 0;
+
+    let mut left = 0;
+    let mut right = 0;
+    while (right < l) || (left < l) {
+        if (consonant_count >= k) && vowel_reached {
+            // increment left
+            result += (l - right + 1) as i64;
+
+            let next = chars[left];
+            if is_vowel(next) {
+                let m = map.get_mut(&next).unwrap();
+                *m -= 1;
+                if *m <= 0 {
+                    map.remove(&next);
+                    vowel_reached = map.len() == 5;
+                }
+            } else {
+                consonant_count -= 1;
+            }
+            left += 1;
+        } else {
+            // consume forwards
+            if right >= l {
+                break;
+            }
+
+            let next = chars[right];
+            if is_vowel(next) {
+                match map.get_mut(&next) {
+                    Some(m) => {
+                        *m += 1;
+                    },
+                    None => {
+                        map.insert(next, 1);
+                        vowel_reached = map.len() == 5;
+                    }
+                }
+            } else {
+                consonant_count += 1;
+            }
+
+            right += 1;
+        }
+    }
+
+    result
+}