Update README.md

README.md

@@ -1,3 +1,5 @@
+### 01背包问题的递归版的精简版
+
 ~~~c
 #include<stdio.h>
 #define max(x,y)((x)>(y)?(x):(y))
@@ -37,4 +39,123 @@ int main(){
 	printf("\n");
 	printf("总价值=%d",maxv);
 }
-~~~
+~~~
+
+### 斐波那契数列递归
+
+~~~c
+#include<stdio.h>
+int fib(int n){
+	if(n<=2){
+		return n;
+	}else{
+		return fib(n-1)+fib(n-2);
+	}
+}
+int main(){
+	int n;
+	printf("请输入想打印的斐波拉契数列：\n");
+	scanf("%d",&n);
+	printf("斐波那契数列：\n");
+	for(int i = 0;i<=n;i++){
+		printf("%d ",fib(i));
+	} 
+	return 0;
+}
+~~~
+
+### 常规的求解众数和重数
+
+~~~c
+#include<stdio.h>
+typedef struct{
+	int number;
+	int count;
+} Mode;
+Mode findMode(int arr[],int n){
+	Mode mode = {arr[0],1};
+	int count = 1;
+	int maxCount = 1;
+	for(int i=0;i<n;i++){
+		if(arr[i] == arr[i-1]){
+			count++;
+		}else{
+			if(count>maxCount){
+				mode.number = arr[i-1];
+				mode.count = count;
+				maxCount = count;
+			}
+			count = 1;
+		}
+	}
+	if(count>maxCount){
+		mode.number = arr[n-1];
+		mode.count = count;
+	}
+	return mode;
+} 
+int main(){
+	int arr[] =  {1,2,2,2,3,3,5,6,6,6,6};
+	int n = sizeof(arr)/sizeof(arr[0]);
+	printf("递增序列: ");
+	for (int i = 0; i < n; i++)//输出待求众数序列中的元素；
+	printf("%d ",arr[i]);
+	printf("\n");
+	Mode result = findMode(arr,n);
+	printf("众数为：%d,重数为：%d",result.number,result.count);
+	return 0;
+}
+~~~
+
+### 二叉树递归版
+
+~~~c
+#include<stdio.h>
+#include<stdlib.h>
+#define max(a,b)((a)>(b)?(a):(b))
+typedef struct TreeNode{
+	int val;
+	struct TreeNode *left;
+	struct TreeNode *right;
+}TreeNode;
+int maxPathHelper(TreeNode *root,int *maxSum){
+	if(root==NULL){
+		return 0;
+	}
+	int leftSum = maxPathHelper(root->left,maxSum);
+	int rightSum = maxPathHelper(root->right,maxSum);
+	int currSum = max(max(root->val,root->val+leftSum+rightSum),
+					max(root->val+leftSum,root->val+rightSum));
+	*maxSum = max(*maxSum,currSum);				 
+	return max(root->val,max(root->val+rightSum,root->val+leftSum));
+} 
+int maxPathSum(TreeNode *root){
+	if(root==NULL){
+		return 0;
+	}
+	int maxSum = 0;
+	maxPathHelper(root,&maxSum);
+	return maxSum;
+}
+TreeNode* createTreeNode(int val){
+	TreeNode* newNode = (TreeNode*)malloc(sizeof(TreeNode));
+	newNode->val=val;
+	newNode->left=NULL;
+	newNode->right=NULL;
+	return newNode; 
+}
+int main(){
+	TreeNode* root = createTreeNode(-10);
+	root->left=createTreeNode(9);
+	root->right=createTreeNode(20);
+	root->right->left=createTreeNode(15);
+	root->right->right=createTreeNode(7);
+	int maxSum = maxPathSum(root);
+	printf("最大的路径和为：%d",maxSum);
+	free(root->left);
+	free(root->right);
+	free(root);
+	return 0; 
+}
+~~~
+