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lswrc.go
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lswrc.go
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package lswrc
import (
"github.com/catorpilor/leetcode/utils"
)
func lengthOfLongestSubstring(s string) int {
n := len(s)
if n <= 1 {
return n
}
// sliding window
left, right, max := 0, 0, 0
hset := make(map[byte]bool)
for right < n {
if hset[s[right]] {
// found in the set
delete(hset, s[left])
left++
} else {
hset[s[right]] = true
right++
max = utils.Max(max, right-left)
}
}
return max
}
func bruteForceLength(s string) int {
n := len(s)
if n <= 1 {
return n
}
max := 0
for i := 0; i < n; i++ {
for j := i + 1; j <= n; j++ {
if allUnique(s, i, j) {
max = utils.Max(max, j-i)
}
}
}
return max
}
func allUnique(s string, l, r int) bool {
hset := make(map[byte]bool)
for i := l; i < r; i++ {
if hset[s[i]] {
return false
}
hset[s[i]] = true
}
return true
}
func lengthOfLongestSubstringOpt(s string) int {
n := len(s)
if n <= 1 {
return n
}
max := 0
hset := make(map[byte]int)
l, r := 0, 0
for r < n {
// expand [l,r]
if k, ok := hset[s[r]]; ok {
l = utils.Max(l, k)
}
max = utils.Max(max, r-l+1)
hset[s[r]] = r + 1
r++
}
return max
}