By | 02.05.2017

# Shortest Path from root to a NULL child

Write a C Program to find Shortest Path from root to a NULL child in Binary Tree. Here’s simple Program to find Shortest Path from root to a NULL child in Binary Tree in C Programming Language.

## What is Tree ?

In linear data structure, data is organized in sequential order and in non-linear data structure, data is organized in random order. Tree is a very popular data structure used in wide range of applications.

A tree data structure can be defined as follows…

• Tree is a non-linear data structure which organizes data in hierarchical structure and this is a recursive definition.

A tree data structure can also be defined as follows…

• Tree data structure is a collection of data (Node) which is organized in hierarchical structure and this is a recursive definition.

Every individual element is called as Node. Node in a tree data structure, stores the actual data of that particular element and link to next element in hierarchical structure.

Below is the source code for Program to find Shortest Paths from root to a NULL child in Binary Tree which is successfully compiled and run on Windows System to produce desired output as shown below :

### SOURCE CODE : :

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 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 /* Program to find Shortest Paths from root to a NULL child in Binary Tree  */   #include #include #define MAX 100   struct node { struct node *lchild; int info; struct node *rchild; };     struct node *insert(struct node *ptr, int ikey); void display(struct node *ptr,int level); int minHt(struct node *p);   int main() { struct node *root=NULL,*ptr; int choice,k,item,path[MAX];   while(1) { printf(“\n”); printf(“1.Insert\n”); printf(“2.Display\n”); printf(“3.Shortest Path\n”); printf(“4.Quit\n”); printf(“\nEnter your choice : “); scanf(“%d”,&choice);   switch(choice) {   case 1: printf(“\nEnter the key to be inserted : “); scanf(“%d”,&k); root = insert(root, k); break;           case 2:             printf(“\n”);             display(root,0);             printf(“\n”);             break;           case 3:             printf(“\n”);             printf(“\nShortest Path from root to a NULL child :: %d\n”,minHt(root));             printf(“\n”);             break;           case 4: exit(1);   default: printf(“\nWrong choice\n”);   }/*End of switch */ }/*End of while */   return 0;   }/*End of main( )*/     struct node *insert(struct node *ptr, int ikey ) { if(ptr==NULL) { ptr = (struct node *) malloc(sizeof(struct node)); ptr->info = ikey; ptr->lchild = NULL; ptr->rchild = NULL; } else if(ikey < ptr->info) /*Insertion in left subtree*/ ptr->lchild = insert(ptr->lchild, ikey); else if(ikey > ptr->info) /*Insertion in right subtree */ ptr->rchild = insert(ptr->rchild, ikey); else printf(“Duplicate key\n”); return(ptr); }/*End of insert( )*/   void display(struct node *ptr,int level) { int i; if(ptr == NULL )/*Base Case*/ return; else     { display(ptr->rchild, level+1); printf(“\n”); for (i=0; iinfo); display(ptr->lchild, level+1); } }/*End of display()*/     /*this will give shortest paths from root to a NULL child and not to a leaf node*/ int minHt(struct node *ptr) { int h_left, h_right;   if (ptr == NULL) return 0;   h_left = minHt(ptr->lchild); h_right = minHt(ptr->rchild);   if( h_left < h_right ) return 1 + h_left; else return 1+ h_right; }

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