123456789在这些数之间可以差如+，-，最后等于某个值的组合数 方法一：递归法 void f2(int index,int opt,int sum,int value,int &amp;count) { for(int i=index;i<=9;i++){ int t=0; for(int m=index;m<=i;m++) t=10*t+m; if(i==9){ sum=sum+opt*t; if(value==sum) count++; return ; } f2(i+1,1,...

#include<stdio.h> #include<stdlib.h> typedef struct binarytree { int data; struct binarytree *lchild; struct binarytree *parent; struct binarytree *rchild; }BT; BT * init_bt() { BT *tree=(BT *)malloc(sizeof(BT)); tree->parent=NULL; tree->lchild=NULL; tree->rchild=NULL;...

问题描述：火车分n小节，从头开始进站出站，有可能的顺序 #include<fstream> #include<sstream> #include<iostream> #include<stack> using namespace std; int main(){ ifstream in("rail.txt"); for(int n,line=0;in>>n&amp;&amp;n&amp;&amp;in.ignore();){ cout<<(line++ ? "\n":""); for(string s;getline(in...

#include<stdio.h> #include<stdlib.h> #include<malloc.h> #include<string.h> typedef struct node { int i; int j; float value; struct node *down; struct node *right; }NODE,*NODEP; typedef struct matrix { int m;int n;int t; NODEP *row; NODE...