Find the node with the smallest value range in the linked list and move it to the front of the linked list

One 、 Title Description

         It is known that the linear linked list consists of list Pointed out that , The construction of chain nodes is （data,next）, Please write an algorithm , Move the node with the smallest value of the data field in the linked list to the front of the linked list .（ You cannot apply for additional nodes ）（ Better reading experience , Please visit Programmers are on the road ）

Two 、 Analysis answers

         The main solution is , Traversing the linked list , Find the smallest node min, And the precursor of this node pre_min, Then move it to the front of the linked list .
         It is worth noting that , Because the node structure requires a one-way single linked list , therefore , If you want to move min, We must find his precursor . If it's a two-way list , You don't need to record the precursor node .

int move_min_to_first(PNode head){
　　PNode pre_p = head->next, p = pre_p->next;
　　// Record the smallest element node and its precursor
　　PNode pre_min = head, min = pre_p;
　　// Judge whether the list is empty
　　if(head == NULL || head->next == NULL){
　　　　return -1;
　　}
　　// Traversing the linked list , Find the smallest element node
　　while§{
　　　　if(min->data > p->data){
　　　　　　pre_min = pre_p;
　　　　　　min = p;
　　　　}
　　　　pre_p = p;
　　　　p = p->next;
　　}
　　// Move to the front of the linked list
　　pre_min->next = min->next;
　　min->next = head->next;
　　head->next = min;
　　return 1;
}

     The complete executable code is as follows ：

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

typedef struct node{
    

	int data;
	struct node *next;

}Node,*PNode;


/*  Way of thinking ：  Traversing the linked list , Find the smallest element node and its precursor node , Then place the smallest node at the front of the linked list .  Return value ： -1  Linked list is empty. , Can't find ; 0  To find the failure ; 1 Find success . */

int move_min_to_first(PNode head){
    

	PNode pre_p = head->next, p = pre_p->next;
    
	// Record the smallest element node and its precursor 
	PNode pre_min = head, min = pre_p;

	// Judge whether the list is empty 
	if(head == NULL || head->next == NULL){
    
	
		return -1;
	}

	// Traversing the linked list , Find the smallest element node 
	while(p){
    
	
		if(min->data > p->data){
    
		
			pre_min = pre_p;
			min = p;
		
		}

		pre_p = p;
		p = p->next;

	}

	// Move to the front of the linked list 
	pre_min->next = min->next;
	min->next = head->next;
	head->next = min;

	return 1;

}

// Head interpolation method to establish a single linked list with head nodes 
PNode creat_list(){
    
 
	// Application header node 
	PNode head = (PNode)malloc(sizeof(Node));
 
	head->next = NULL;
	scanf("%d",&(head->data)); //  The data field of the header node can store summary points 
 
	// New elements 
	PNode p =  NULL;
	int i;
	for(i=0;i<(head->data);i++){
    
	
		p = (PNode)malloc(sizeof(Node));
 
		scanf("%d",&(p->data));
		
		// This is the key of head insertion 
		p->next = head->next;
		head->next = p;
 
	}
	return head;
 
}
 
void print_list(PNode head){
    
 
		PNode p = head->next;
 
		while(p){
    
		
			printf("p->data: %d \t",p->data);
 
			p = p->next;
		
		}
		printf("\n");
 
}
  int main(){
    
  
	  PNode head = creat_list();
 
	  print_list(head);
 
	  move_min_to_first(head);
 
	  print_list(head);
 
	  return 0;
  
  }