题意:有一串数字,每一次你可以使一个数字减少a,使相邻两个数字减少b,只能操作2-n-1次
思路:直接暴力DFS一波...
#include<bits/stdc++.h>
using namespace std;
int ans=1e9,h[15],n,a,b;
vector<int> T,T2;
void dfs(int x,int times)
{
if(times>=ans)return;
if(x==n)
{
if(h[x]<0)
{
T2=T;
ans=times;
}
return;
}
for(int i=0;i<=max(h[x-1]/b+1,max(h[x]/a+1,h[x+1]/b+1));i++)
{
if(h[x-1]<b*i)
{
h[x-1]-=b*i;
h[x]-=a*i;
h[x+1]-=b*i;
for(int j=0;j<i;j++)T.push_back(x);
dfs(x+1,times+i);
for(int j=0;j<i;j++)T.pop_back();
h[x-1]+=b*i;
h[x]+=a*i;
h[x+1]+=b*i;
}
}
}
int main()
{
scanf("%d%d%d",&n,&a,&b);
for(int i=1;i<=n;i++)scanf("%d",&h[i]);
dfs(2,0);
cout<<ans<<endl;
for(int i=0;i<T2.size();i++)
cout<<T2[i]<<" ";
cout<<endl;
}
Description
This is simplified version of the problem used on the original contest. The original problem seems to have too difiicult solution. The constraints for input data have been reduced.
Polycarp likes to play computer role-playing game «Lizards and Basements». At the moment he is playing it as a magician. At one of the last levels he has to fight the line of archers. The only spell with which he can damage them is a fire ball. If Polycarp
hits the i-th archer with his fire ball (they are numbered from left to right), the archer loses a health points. At the same
time the spell damages the archers adjacent to the i-th (if any) — they lose b (1 ≤ b < a ≤ 10)
health points each.
As the extreme archers (i.e. archers numbered 1 and n) are very far, the fire ball cannot reach them. Polycarp can hit any other archer with his fire ball.
The amount of health points for each archer is known. An archer will be killed when this amount is less than 0. What is the minimum amount of spells Polycarp can use to kill all the enemies?
Polycarp can throw his fire ball into an archer if the latter is already killed.
Output
In the first line print t — the required minimum amount of fire balls.
In the second line print t numbers — indexes of the archers that Polycarp should hit to kill all the archers in t shots. All
these numbers should be between 2 and n - 1. Separate numbers with spaces. If there are several solutions, output any of them. Print numbers in any order.