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update 91

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This commit is contained in:
novahe
2021-05-24 23:16:08 +08:00
parent 44c68a333a
commit 38875b19fb
2 changed files with 12 additions and 38 deletions
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25
leetcode/0091.Decode-Ways/91. Decode Ways.go
View File

@ -1,29 +1,16 @@
package leetcode
import (
"strconv"
)
func numDecodings(s string) int {
if len(s) == 0 {
return 0
}
dp := make([]int, len(s)+1)
n := len(s)
dp := make([]int, n+1)
dp[0] = 1
if s[:1] == "0" {
dp[1] = 0
} else {
dp[1] = 1
}
for i := 2; i <= len(s); i++ {
lastNum, _ := strconv.Atoi(s[i-1 : i])
if lastNum >= 1 && lastNum <= 9 {
for i := 1; i <= n; i++ {
if s[i-1] != '0' {
dp[i] += dp[i-1]
}
lastNum, _ = strconv.Atoi(s[i-2 : i])
if lastNum >= 10 && lastNum <= 26 {
if i > 1 && s[i-2] != '0' && (s[i-2]-'0')*10+(s[i-1]-'0') <= 26 {
dp[i] += dp[i-2]
}
}
return dp[len(s)]
return dp[n]
}

25
website/content/ChapterFour/0001~0099/0091.Decode-Ways.md
View File

@ -51,32 +51,19 @@ Given a **non-empty** string containing only digits, determine the total numbe
package leetcode
import (
"strconv"
)
func numDecodings(s string) int {
if len(s) == 0 {
return 0
}
dp := make([]int, len(s)+1)
n := len(s)
dp := make([]int, n+1)
dp[0] = 1
if s[:1] == "0" {
dp[1] = 0
} else {
dp[1] = 1
}
for i := 2; i <= len(s); i++ {
lastNum, _ := strconv.Atoi(s[i-1 : i])
if lastNum >= 1 && lastNum <= 9 {
for i := 1; i <= n; i++ {
if s[i-1] != '0' {
dp[i] += dp[i-1]
}
lastNum, _ = strconv.Atoi(s[i-2 : i])
if lastNum >= 10 && lastNum <= 26 {
if i > 1 && s[i-2] != '0' && (s[i-2]-'0')*10+(s[i-1]-'0') <= 26 {
dp[i] += dp[i-2]
}
}
return dp[len(s)]
return dp[n]
}
```