leetcode/src/114.c at master · lennylxx/leetcode · GitHub

Name: leetcode/src/114.c at master · lennylxx/leetcode · GitHub
Rating: 4.4 (2925 reviews)
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#include<stdio.h>
#include<stdlib.h>
#include<assert.h>

structTreeNode {
intval;
structTreeNode*left;
structTreeNode*right;
};

voidflattenHelper(structTreeNode*root, structTreeNode**start, structTreeNode**end){
if (root==NULL) {
*start=*end=NULL;
return;
 }
structTreeNode*lstart, *lend, *rstart, *rend;
lstart=lend=rstart=rend=NULL;

flattenHelper(root->left, &lstart, &lend);
flattenHelper(root->right, &rstart, &rend);

root->left=NULL;

if (lend!=NULL) {
root->right=lstart;
lend->right=rstart;
 }
else {
root->right=rstart;
 }

*start=root;

if (rend!=NULL) {
*end=rend;
 }
elseif (lend!=NULL) {
*end=lend;
 }
else {
*end=root;
 }
}

voidflatten(structTreeNode*root) {
structTreeNode*start, *end;
start=end=NULL;

flattenHelper(root, &start, &end);
}

intmain() {
structTreeNode*root= (structTreeNode*)calloc(3, sizeof(structTreeNode));
root->val=1;
root->left=root+1;
root->left->val=2;
root->left->left=root+2;
root->left->left->val=3;

flatten(root);

while (root) {
assert(root->left==NULL);
printf("%d ", root->val);
root=root->right;
 }
printf("\n");

return0;
}