countHi - Recursive

Given a string, compute recursively (no loops) the number of times lowercase "hi" appears in the string. countHi("xxhixx") → 1 countHi("xhixhix") → 2 countHi("hi") → 1

C# :

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public static int countHi(String str) { //stop condition if (str.Length < 2) return 0; //Process int index = str.IndexOf("hi"); if (index < 0) return 0; return 1 + countHi(str.Substring(index + 1, str.Length - (1 + index))); }

Result :