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Commit 861c770

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Merge pull request youngyangyang04#2866 from twoliang/master
0151.翻转字符串里的单词、44. 开发商购买土地(卡码网):go版本解法、738.调递增的数字:原go版本答案有错误,已更正
2 parents 5cd1eec + aa6f361 commit 861c770

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‎problems/0151.翻转字符串里的单词.md

Lines changed: 40 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -639,7 +639,46 @@ func reverse(b []byte) {
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}
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}
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```
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```go
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//双指针解法。指针逆序遍历,将遍历后得到的单词(间隔为空格,用以区分)顺序放置在额外空间
644+
//时间复杂度O(n),空间复杂度O(n)
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func reverseWords(s string) string {
646+
strBytes := []byte(s)
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n := len(strBytes)
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// 记录有效字符范围的起始和结束位置
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start, end := 0, n-1
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// 去除开头空格
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for start < n && strBytes[start] == 32 {
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start++
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}
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// 处理全是空格或空字符串情况
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if start == n {
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return ""
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}
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// 去除结尾空格
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for end >= 0 && strBytes[end] == 32 {
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end--
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}
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// 结果切片,预分配容量
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res := make([]byte, 0, end-start+1)//这里挺重要的,本人之前没有预分配容量,每次循环都添加单词,导致内存超限(也可能就是我之前的思路有问题)
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// 从后往前遍历有效字符范围
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for i := end; i >= start; {
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// 找单词起始位置,直接通过循环条件判断定位
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for ; i >= start && strBytes[i] == 32; i-- {
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}
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j := i
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for ; j >= start && strBytes[j]!= 32; j-- {
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}
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res = append(res, strBytes[j+1:i+1]...)
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// 只在不是最后一个单词时添加空格
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if j > start {
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res = append(res, 32)
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}
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i = j
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}
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return string(res)
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}
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```
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### JavaScript:

‎problems/0738.单调递增的数字.md

Lines changed: 15 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -273,22 +273,20 @@ class Solution:
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### Go
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```go
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func monotoneIncreasingDigits(n int) int {
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s := strconv.Itoa(N)//将数字转为字符串,方便使用下标
277-
ss := []byte(s)//将字符串转为byte数组,方便更改。
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n := len(ss)
279-
if n <= 1 {
280-
return n
281-
}
282-
for i := n-1; i > 0; i-- {
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if ss[i-1] > ss[i] { //前一个大于后一位,前一位减1,后面的全部置为9
284-
ss[i-1] -= 1
285-
for j := i; j < n; j++ { //后面的全部置为9
286-
ss[j] = '9'
287-
}
288-
}
289-
}
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res, _ := strconv.Atoi(string(ss))
291-
return res
276+
s := strconv.Itoa(n)
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// 从左到右遍历字符串,找到第一个不满足单调递增的位置
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for i := len(s) - 2; i >= 0; i-- {
279+
if s[i] > s[i+1] {
280+
// 将该位置的数字减1
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s = s[:i] + string(s[i]-1) + s[i+1:]
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// 将该位置之后的所有数字置为9
283+
for j := i + 1; j < len(s); j++ {
284+
s = s[:j] + "9" + s[j+1:]
285+
}
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}
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}
288+
result, _ := strconv.Atoi(s)
289+
return result
292290
}
293291
```
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@@ -447,3 +445,4 @@ public class Solution
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<a href="https://programmercarl.com/other/kstar.html" target="_blank">
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<img src="../pics/网站星球宣传海报.jpg" width="1000"/>
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</a>
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‎problems/kamacoder/0044.开发商购买土地.md

Lines changed: 86 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -527,3 +527,89 @@ int main()
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}
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```
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### Go
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前缀和
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```go
536+
package main
537+
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import (
539+
"fmt"
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"os"
541+
"bufio"
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"strings"
543+
"strconv"
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"math"
545+
)
546+
547+
func main() {
548+
var n, m int
549+
550+
reader := bufio.NewReader(os.Stdin)
551+
552+
line, _ := reader.ReadString('\n')
553+
line = strings.TrimSpace(line)
554+
params := strings.Split(line, " ")
555+
556+
n, _ = strconv.Atoi(params[0])
557+
m, _ = strconv.Atoi(params[1])//n和m读取完成
558+
559+
land := make([][]int, n)//土地矩阵初始化
560+
561+
for i := 0; i < n; i++ {
562+
line, _ := reader.ReadString('\n')
563+
line = strings.TrimSpace(line)
564+
values := strings.Split(line, " ")
565+
land[i] = make([]int, m)
566+
for j := 0; j < m; j++ {
567+
value, _ := strconv.Atoi(values[j])
568+
land[i][j] = value
569+
}
570+
}//所有读取完成
571+
572+
//初始化前缀和矩阵
573+
preMatrix := make([][]int, n+1)
574+
for i := 0; i <= n; i++ {
575+
preMatrix[i] = make([]int, m+1)
576+
}
577+
578+
for a := 1; a < n+1; a++ {
579+
for b := 1; b < m+1; b++ {
580+
preMatrix[a][b] = land[a-1][b-1] + preMatrix[a-1][b] + preMatrix[a][b-1] - preMatrix[a-1][b-1]
581+
}
582+
}
583+
584+
totalSum := preMatrix[n][m]
585+
586+
minDiff := math.MaxInt32//初始化极大数,用于比较
587+
588+
//按行分割
589+
for i := 1; i < n; i++ {
590+
topSum := preMatrix[i][m]
591+
592+
bottomSum := totalSum - topSum
593+
594+
diff := int(math.Abs(float64(topSum - bottomSum)))
595+
if diff < minDiff {
596+
minDiff = diff
597+
}
598+
}
599+
600+
//按列分割
601+
for j := 1; j < m; j++ {
602+
topSum := preMatrix[n][j]
603+
604+
bottomSum := totalSum - topSum
605+
606+
diff := int(math.Abs(float64(topSum - bottomSum)))
607+
if diff < minDiff {
608+
minDiff = diff
609+
}
610+
}
611+
612+
fmt.Println(minDiff)
613+
}
614+
```
615+

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