//貌似有测试用例没通过。。。不知道哪里做的不对。。。
//
// main.cpp
// 11_29
//
// Created by 韩雪滢 on 11/29/16.
// Copyright ? 2016 韩雪滢. All rights reserved.
//
#include <iostream>
using namespace std;
#define MAX 10000000
int step = MAX;
int currentStep = 0;
int start,terminal;
class Node{
public:
int index;
int *edge;
int num;
Node(int i){
index = i;
calEdge();
}
void calEdge(){
num = 0;
int *tempedge = new int[index];
for(int i=2;i<index/2;i++){
if(index % i == 0)
{
tempedge[num] = i;
num++;
}
}
if(num >0){
edge = new int[num-1];
for(int j=0;j< num;j++)
edge[j] = tempedge[j];
}
}
};
void findStepNum(int s){
Node startNode(s);
for(int i=0;i<startNode.num;i++){
int nextNode = startNode.index + startNode.edge[i];
if(nextNode < terminal){
currentStep ++;
findStepNum(nextNode);
}
if(nextNode == terminal){
if(currentStep != 0 && currentStep < step){
step = currentStep;
break;
}
}
}
currentStep--;
}
int main(int argc, const char * argv[]) {
cin >> start >> terminal;
findStepNum(start);
if(step != MAX)
cout << ++step <<endl;
else
cout << -1 << endl;
return 0;
正解：
#include<iostream>
#include<vector>
#include<set>
#include<math.h>
using namespace std;
void get_yue_shu(int n, vector<int>&a){
for(int i=2;i<=sqrt(n);i++){
if(n%i==0){
a.push_back(i);
if(n/i != i)
a.push_back(n/i);
}
}
}
int main(){
int n,m;
while(cin>>n>>m){
vector<int> res(m+1, 0);
res[n] = 1;
for(int i=n;i<=m;i++){
vector<int>a;
//位置i无法到达，跳过
if(res[i]==0)
continue;
get_yue_shu(i, a);
//记录从起点到i的最小步数
for(int j=0;j<a.size();j++){
//由点i出发能到达的点
if((a[j]+i)<=m&&res[a[j]+i]!=0)
//其它点也能到达，比较大小，记录最小步数
res[a[j]+i] = min(res[a[j]+i], res[i] + 1);
else if((a[j]+i)<=m)
//到达点i的最小步数加1
res[a[j]+i] = res[i] + 1;
}
}
if(res[m]==0)
cout<<-1<<endl;
else
cout<<res[m]-1<<endl;
}
return 0;
}