Do daily and similar questions

Author: Zanger67

my-submissions/m1358 v2.py

@@ -0,0 +1,11 @@
+class Solution:
+    def numberOfSubstrings(self, s: str) -> int:
+        abc = [-1, -1, -1]
+        output = 0
+
+        for i, x in enumerate(s) :
+            abc[ord(x) - ord('a')] = i
+            if -1 not in abc :
+                output += 1 + min(abc)
+
+        return output

my-submissions/m2063 v1.py

@@ -0,0 +1,8 @@
+class Solution:
+    def countVowels(self, word: str) -> int:
+        vows = set('aeiou')
+        output = 0
+        for i, c in enumerate(word) :
+            if c in vows :
+                output += i * (len(word) - i - 1) + len(word)
+        return output

my-submissions/m2063 v2.py

@@ -0,0 +1,4 @@
+class Solution:
+    def countVowels(self, word: str) -> int:
+        vows = set('aeiou')
+        return sum(i * (len(word) - i - 1) + len(word) for i, c in enumerate(word) if c in vows)

my-submissions/m2063 v3 oneliner.py

@@ -0,0 +1,3 @@
+class Solution:
+    def countVowels(self, word: str) -> int:
+        return sum(i * (len(word) - i - 1) + len(word) for i, c in enumerate(word) if c in 'aeiou')

my-submissions/m2063.md

@@ -0,0 +1,80 @@
+### Notes and Scratch Work
+
+```
+n = Total length of word
+v = Number of vowels in word
+
+aba
+    a   1
+    b   0
+    a   1
+    ab  1
+    ba  1
+    aba 2
+
+This is the same as doing "aaaa" instead of "aba" --> becomes 4 choose 2 = 6
+
+abc
+    a   1
+    b   0
+    c   0
+    ab  1
+    bc  0
+    abc 1
+
+    abc -> aaa -> 3 choose 1 = 3
+
+abba
+    a       1
+    b       0
+    b       0
+    a       1
+
+    ab      1
+    bb      0
+    ba      1
+
+    abb     1
+    bba     1
+
+    abba    2
+
+    Total: (1)+(1+1)+(1+1+1)+(2) = 8
+    abba --> aaaba --> aaaaaa --> 6 choose 2 = 15 WRONG
+    abba -> aaba --> aaaaa -> 5 choose 2 = 10 WRONG
+    abba -> aaaa --> 4 choose 2 = 6 WRONG
+
+    contributions:
+    a   4
+    b   0
+    b   0
+    a   4
+
+abab
+    a       1
+    b       0
+    a       1
+    b       0
+
+    ab      1
+    ba      1
+    ab      1
+
+    aba     2
+    bab     1
+
+    abab    2
+
+    Total = 2+3+3+2 = 10
+
+    contributions:
+    a   4 = 0 * 3 + 4
+    b   0
+    a   6 = (left * right) + total string length = 2 * 1 + 4
+    b   0
+
+```
+
+**Realization**: Each vowel contributes the following to the output:
+
+$$(\text{characters left}) * (\text{characters right}) + \text{word length}$$