# Notes for Radish

## WSL
### Command

# 回主目錄 (home folder)
$ cd
neo@bala:/mnt/c/Users/neowong$ cd
neo@bala:~$

# 印出目前目錄
$ pwd
neo@bala:~$ pwd
/home/neo

# 到 My Document
neo@bala:~$ cd /mnt/c/Users/neo/Documents/
neo@bala:/mnt/c/Users/neo/Documents$

### Access WSL Linux file from Windows

in 檔案總管 : \\WSL$

## unordered_map sample

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <sstream>
#include <unordered_map>
#include <set>
#include <algorithm>
#include <cmath>
#include <cwctype>
#include <locale>

using namespace std;

//#define DEBUG

struct xxx {
	int data;
	struct xxx* parent;
};

int main(int argc, const char * argv[] ) {
	unordered_map<int, xxx*> in;
	struct xxx *a = new xxx;
	struct xxx *b = new xxx;
	struct xxx *c = NULL;


	// Add 0, and it's map to xxx
	a->data = 0;
	a->parent = NULL; // means a is a root
	in[a->data] = a;

	// b's parent is a, and add 0
	b->data = 2;
	b->parent = a;
	in[b->data] = b;

	// Search 2, and print out
	c = in[2];
	cout << c->data << endl; // should be 2

	// get its parent
	c = c->parent;
	cout << c->data << endl; // should be 0
    
    // loop map
    // will be 
    //  2:2
    //  0:0
    for (auto& it: in) {
        cout << it.first << ":" << it.second->data << endl;
    }

	return 0;
}

# Link list
### Link list in C

#include <stdio.h>
#include <stdlib.h>

// define a node struct
struct node {
	int data;
	struct node *next;
};

typedef struct node node_t;

// new a node with data assigned 
node_t * new_node(int d) {
	node_t *t;
	t=(node_t*)malloc(sizeof(node_t));
	if(t==NULL)
		return NULL;
	t->data = d;
	t->next = NULL;
	return t;
}

// add node into end of link list
void add_node(node_t* h, node_t* n) {
    node_t * c = h;
    while (c->next != NULL) {
        c = c->next;
    }

    /* now we can add a new variable */
    c->next = n;
}

// start from head loop list
void print_list(node_t * n) {
    node_t * c = n;

    while (c != NULL) {
        printf("%d\n", c->data);
        c = c->next;
    }
}

// find node - sequence search
node_t * find_node(node_t *h, int d) {
    node_t * c = h;

    while (c != NULL) {
		printf( "[%d]", c->data);
		if(c->data == d)
			return c;
		c = c->next;
    }
	return NULL;
}

int main( int argc, char** argv){

	node_t *head = NULL;
	node_t *n = NULL;

	// new a head
	head = new_node(0);
	if(head!=NULL)
		printf( "Head data : %d\n", head->data);

	// add two node
	n = new_node(1);
	add_node(head,n);

	n = new_node(2);
	add_node(head,n);

	// print list
	print_list(head);

	// find
	n = find_node(head,2);
	if(n!=NULL)
		printf( "2 found\n");

	return 0;
}

### Link list in C w/ binary search

#include <stdio.h>
#include <stdlib.h>

// define a node struct
typedef struct node {
	int data;
	struct node *next;
} node_t;

node_t * new_node(int d) {
	node_t *t;
	t=(node_t*)malloc(sizeof(node_t));
	if(t==NULL)
		return NULL;
	t->data = d;
	t->next = NULL;
	return t;
}

// Function to insert a node into the sorted linked list
void add_node_sorted(node_t** h, node_t*n ) {

    if (*h == NULL || n->data < (*h)->data) {
        n->next = *h;
        *h = n;
    } else {
        node_t * c = *h;
        while (c->next != NULL && c->next->data < n->data) {
            c = c->next;
        }
        n->next = c->next;
        c->next = n;
    }
}

void add_node(node_t* h, node_t* n) {
    node_t * c = h;
    while (c->next != NULL) {
        c = c->next;
    }

    /* now we can add a new variable */
    c->next = n;
}

void print_list(node_t * n) {
    node_t * c = n;

    while (c != NULL) {
        printf("%d\n", c->data);
        c = c->next;
    }
}

node_t * find_node(node_t *h, int d) {
    node_t * c = h;

    while (c != NULL) {
		printf( "[%d]", c->data);
		if(c->data == d)
			return c;
		c = c->next;
    }
	return NULL;
}

// Function for faster search in the sorted linked list
node_t * binarySearch(node_t *h, int data) {
    node_t *low = h;
    node_t *high = NULL;

    while (low != high) {
        node_t *mid = low;
        while (mid->next != high) {
            mid = mid->next;
        }
        int midValue = mid->data;

        if (midValue == data) {
            return mid;
        } else if (midValue < data) {
            low = mid->next;
        } else {
            high = mid;
        }
    }
    return NULL; // Element not found
}

int main( int argc, char** argv){

	node_t *head = NULL;
	node_t *n = NULL;

	add_node_sorted( &head, new_node(5) );
	add_node_sorted( &head, new_node(2) );
	add_node_sorted( &head, new_node(6) );
	add_node_sorted( &head, new_node(0) );
	add_node_sorted( &head, new_node(8) );
	print_list(head);

	n = binarySearch(head,6);

	if(n==NULL)
		printf( "no found\n");
	else
		printf("found: %d\n", n->data);

	return 0;
}

# tips-n-tricks

### Use scanf read unknow number of input

int scanf_command( int *op1, int *op2)
{
    char str[20];
    while (scanf("%s", str)==1)
    {
       if(strcmp(str,"union")==0) {
            if(scanf("%d",op1)!=1) continue;
            if(scanf("%d",op2)!=1) continue;
            return 0; //union
        } else if(strcmp(str,"find")==0) {
            if(scanf("%d",op1)!=1) continue;
            return 1; //find
        } else if(strcmp(str,"same")==0) {
            if(scanf("%d",op1)!=1) continue;
            if(scanf("%d",op2)!=1) continue;
            return 2; //same
        }
    }
    return -1;
}

int main()
{
    int op1, op2, cmd;
    while(1){
        cmd = scanf_command( &op1, &op2);
        if(cmd==1)
            printf( "%d: %d\n", cmd, op1 );
        else
            printf( "%d: %d,%d\n", cmd, op1, op2 );
    }

    return 0;
}

### Read stdin sample
<pre>
</pre>

### Read file sample
<pre>
</pre>

### Use vscode with WSL
<pre>
$ cd <workfolder>
$ code .
</pre>

# Linux shell command sample
### Find string in a text file

$ grep -e \ 11\  -e 7763 -e 4958 input_02.txt 
union 7763 4958
union 8738 4958
union 11 7763
union 7909 4958
find 7763
same 7763 7133
union 4958 7070

# git cheat book
### 檢視提交的歷史記錄

$ git log
commit ca82a6dff817ec66f44342007202690a93763949
Author: Scott Chacon <[e-mail]>
Date:   Mon Mar 17 21:52:11 2008 -0700

### 顯示每筆提交所做的修改內容

$ git log -p
commit ca82a6dff817ec66f44342007202690a93763949
Author: Scott Chacon <[e-mail]>
Date:   Mon Mar 17 21:52:11 2008 -0700

    changed the version number

diff --git a/Rakefile b/Rakefile
index a874b73..8f94139 100644
--- a/Rakefile
+++ b/Rakefile
@@ -5,7 +5,7 @@ require 'rake/gempackagetask'
 spec = Gem::Specification.new do |s|
     s.platform  =   Gem::Platform::RUBY
     s.name      =   "simplegit"
-    s.version   =   "0.1.0"
+    s.version   =   "0.1.1"

### 取得一個 Git 倉儲 - 在現有資料夾中初始化倉儲

$ git init
$ git add <file>
$ git commit -m "init balabala"

### 取得一個 Git 倉儲 - 克隆現有的倉儲

$ git clone https://github.com/bala/bala.git

### 檢查你的檔案狀態

$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working directory clean

### 比對尚未預存的修改

$ git diff
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8ebb991..643e24f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -65,7 +65,8 @@ branch directly, things can get messy.
 Please include a nice description of your changes when you submit your PR;
 if we have to read the whole diff to figure out why you're contributing
 in the first place, you're less likely to get feedback and have your change
-merged in.
+merged in. Also, split your changes into comprehensive chunks if your patch is

### 提交你的修改

$ git commit -m "balabala"

### Reference link
* https://mycollegenotebook.medium.com/c%E8%AA%9E%E8%A8%80%E7%AD%86%E8%A8%98-%E6%8C%87%E6%A8%99-pointers-d28edcdd6283
* [Git介紹](https://git-scm.com/book/zh-tw/v2)

### RISC-V
* https://wen00072.github.io/blog/2015/12/10/about-inline-asm/
* https://msyksphinz-self.github.io/riscv-isadoc/html/index.html