From aa2450222d48ae248a31b15bbcab6484a5fc3967 Mon Sep 17 00:00:00 2001 From: 1ltwo Date: Fri, 3 Jan 2025 10:11:06 +0800 Subject: [PATCH 1/3] =?UTF-8?q?go=E7=89=88=E6=9C=AC=E6=96=B0=E8=A7=A3?= =?UTF-8?q?=E6=B3=95=EF=BC=9A=E5=8F=8C=E6=8C=87=E9=92=88=E9=80=86=E5=BA=8F?= =?UTF-8?q?=E9=81=8D=E5=8E=86=EF=BC=8C=E6=97=B6=E9=97=B4=E5=A4=8D=E6=9D=82?= =?UTF-8?q?=E5=BA=A6O(n)=EF=BC=8C=E7=A9=BA=E9=97=B4=E5=A4=8D=E6=9D=82?= =?UTF-8?q?=E5=BA=A6O(n)?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0151.翻转字符串里的单词.md | 41 +++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/problems/0151.翻转字符串里的单词.md b/problems/0151.翻转字符串里的单词.md index 7c0b7cb1..3dbd59b9 100644 --- a/problems/0151.翻转字符串里的单词.md +++ b/problems/0151.翻转字符串里的单词.md @@ -639,7 +639,46 @@ func reverse(b []byte) { } } ``` - +```go +//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 +//时间复杂度O(n)，空间复杂度O(n) +func reverseWords(s string) string { + strBytes := []byte(s) + n := len(strBytes) + // 记录有效字符范围的起始和结束位置 + start, end := 0, n-1 + // 去除开头空格 + for start < n && strBytes[start] == 32 { + start++ + } + // 处理全是空格或空字符串情况 + if start == n { + return "" + } + // 去除结尾空格 + for end >= 0 && strBytes[end] == 32 { + end-- + } + // 结果切片，预分配容量 + 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） + // 从后往前遍历有效字符范围 + for i := end; i >= start; { + // 找单词起始位置，直接通过循环条件判断定位 + for ; i >= start && strBytes[i] == 32; i-- { + } + j := i + for ; j >= start && strBytes[j]!= 32; j-- { + } + res = append(res, strBytes[j+1:i+1]...) + // 只在不是最后一个单词时添加空格 + if j > start { + res = append(res, 32) + } + i = j + } + return string(res) +} +``` ### JavaScript: From ba5e1b443f8c5b80ccf5f7a34d3ee2b89cd34d47 Mon Sep 17 00:00:00 2001 From: 1ltwo Date: Tue, 7 Jan 2025 22:30:25 +0800 Subject: [PATCH 2/3] =?UTF-8?q?go=E7=89=88=E6=9C=AC=E8=A7=A3=E6=B3=95?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../kamacoder/0044.开发商购买土地.md | 86 +++++++++++++++++++ 1 file changed, 86 insertions(+) diff --git a/problems/kamacoder/0044.开发商购买土地.md b/problems/kamacoder/0044.开发商购买土地.md index 739e2cad..6ef46f21 100644 --- a/problems/kamacoder/0044.开发商购买土地.md +++ b/problems/kamacoder/0044.开发商购买土地.md @@ -526,3 +526,89 @@ int main() } ``` + +### Go + +前缀和 + +```go +package main + +import ( + "fmt" + "os" + "bufio" + "strings" + "strconv" + "math" +) + +func main() { + var n, m int + + reader := bufio.NewReader(os.Stdin) + + line, _ := reader.ReadString('\n') + line = strings.TrimSpace(line) + params := strings.Split(line, " ") + + n, _ = strconv.Atoi(params[0]) + m, _ = strconv.Atoi(params[1])//n和m读取完成 + + land := make([][]int, n)//土地矩阵初始化 + + for i := 0; i < n; i++ { + line, _ := reader.ReadString('\n') + line = strings.TrimSpace(line) + values := strings.Split(line, " ") + land[i] = make([]int, m) + for j := 0; j < m; j++ { + value, _ := strconv.Atoi(values[j]) + land[i][j] = value + } + }//所有读取完成 + + //初始化前缀和矩阵 + preMatrix := make([][]int, n+1) + for i := 0; i <= n; i++ { + preMatrix[i] = make([]int, m+1) + } + + for a := 1; a < n+1; a++ { + for b := 1; b < m+1; b++ { + preMatrix[a][b] = land[a-1][b-1] + preMatrix[a-1][b] + preMatrix[a][b-1] - preMatrix[a-1][b-1] + } + } + + totalSum := preMatrix[n][m] + + minDiff := math.MaxInt32//初始化极大数，用于比较 + + //按行分割 + for i := 1; i < n; i++ { + topSum := preMatrix[i][m] + + bottomSum := totalSum - topSum + + diff := int(math.Abs(float64(topSum - bottomSum))) + if diff < minDiff { + minDiff = diff + } + } + + //按列分割 + for j := 1; j < m; j++ { + topSum := preMatrix[n][j] + + bottomSum := totalSum - topSum + + diff := int(math.Abs(float64(topSum - bottomSum))) + if diff < minDiff { + minDiff = diff + } + } + + fmt.Println(minDiff) +} +``` + From 8bf4e2cdf1f69ab9a8f733e0c5693236335cff5c Mon Sep 17 00:00:00 2001 From: 1ltwo Date: Mon, 27 Jan 2025 16:08:27 +0800 Subject: [PATCH 3/3] =?UTF-8?q?738go=E7=89=88=E6=9C=AC=E7=AD=94=E6=A1=88?= =?UTF-8?q?=E6=9B=B4=E6=AD=A3=EF=BC=88=E5=8E=9F=E7=AD=94=E6=A1=88=E5=8A=9B?= =?UTF-8?q?=E6=89=A3=E6=97=A0=E6=B3=95=E9=80=9A=E8=BF=87=EF=BC=89?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0738.单调递增的数字.md | 31 +++++++++++++------------- 1 file changed, 15 insertions(+), 16 deletions(-) diff --git a/problems/0738.单调递增的数字.md b/problems/0738.单调递增的数字.md index ff438e98..f2cfee04 100644 --- a/problems/0738.单调递增的数字.md +++ b/problems/0738.单调递增的数字.md @@ -273,22 +273,20 @@ class Solution: ### Go ```go func monotoneIncreasingDigits(n int) int { - s := strconv.Itoa(N)//将数字转为字符串，方便使用下标 - ss := []byte(s)//将字符串转为byte数组，方便更改。 - n := len(ss) - if n <= 1 { - return n - } - for i := n-1; i > 0; i-- { - 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 - ss[i-1] -= 1 - for j := i; j < n; j++ { //后面的全部置为9 - ss[j] = '9' - } - } - } - res, _ := strconv.Atoi(string(ss)) - return res + s := strconv.Itoa(n) + // 从左到右遍历字符串，找到第一个不满足单调递增的位置 + for i := len(s) - 2; i >= 0; i-- { + if s[i] > s[i+1] { + // 将该位置的数字减1 + s = s[:i] + string(s[i]-1) + s[i+1:] + // 将该位置之后的所有数字置为9 + for j := i + 1; j < len(s); j++ { + s = s[:j] + "9" + s[j+1:] + } + } + } + result, _ := strconv.Atoi(s) + return result } ``` @@ -447,3 +445,4 @@ public class Solution +