longestCommonPrefix.go

// longestCommonPrefix returns the string in compares that has the longest common prefix with s
func longestCommonPrefix(s string, compares ...string) string {
	var longestMatched int
	var longestCmp string
	maxLength := len(s)
	for _, c := range compares {
		cmpLen := len(c)
		if cmpLen > maxLength {
			cmpLen = maxLength
		}
		if cmpLen <= longestMatched {
			// Already have a longer match, so skip this
			continue
		}
		matched := cmpLen
		for i := 0; i < cmpLen; i++ {
			if c[i] != s[i] {
				matched = i
				break
			}
		}
		if matched > longestMatched {
			// Record longest match seen yet
			longestCmp = c
			if matched == maxLength {
				// Found longest possible match; done
				break
			}
			longestMatched = matched
		}
	}
	return longestCmp
}