package main
import (
"fmt"
"strings"
)
// Non‑overlapping occurrences are matches of a substring that do not reuse any of
// the same characters. Once one match is counted, the next search must begin
// after that match ends.
func countNonOverlapping(haystack string, needle string) int {
/*
Count how many times 'needle' appears in 'haystack' without overlapping.
The algorithm:
• Use strings.Index() to locate the next occurrence.
• Each time a match is found, move the search index forward
by the full length of the matched substring.
• This ensures no characters are reused between matches.
*/
count := 0
index := 0 // current search position in the main string
// Continue searching until Index returns -1 (meaning: no more matches)
for {
// Find the next occurrence starting at the current index
pos := strings.Index(haystack[index:], needle)
if pos == -1 {
// No more matches found
break
}
// We found a match, so increment the count
count++
// Move index forward by the length of the needle
// This ensures the next search begins *after* the matched substring
index += pos + len(needle)
}
return count
}
// ---------------------------------------------------------------
func main() {
// Demonstration using the string provided in the instructions:
s := "go java phphp rust c pphpp c++ phpphp python php phphp"
substring := "php"
// Count non-overlapping occurrences
result := countNonOverlapping(s, substring)
fmt.Println("Non-overlapping occurrences:", result)
}
/*
run:
Non-overlapping occurrences: 6
*/
