1495 非常可乐
文章目录
题目：
思路：
还是多补充一点：只要能抽象出表示状态的点和表示状态转移方式的边就可以搜索答案，这也是DFS和BFS用处广泛而强大的原因之一，经过抽象，可以解决很多的问题。
时间复杂度：
AC代码：
#include<bits/stdc++.h>
typedef long long ll;
const int N = 1e2+5,M = 2e4+10,INF = 0x3f3f3f3f,mod = 1e9+7;
struct Node{
int x,y,z,step;
}que[N*N*N*3];
int a,b,c;
bool book[N][N][N];
void bfs()
{
if(a&1)
{
std::cout<<"NO\n";
return;
}
int head = 0,tail = -1;
que[++tail] = {a,0,0};
book[a][0][0] = true;
while(tail >= head)
{
auto temp = que[head++];
if((temp.x==a/2)+(temp.y==a/2)+(temp.z==a/2)==2)
{
std::cout<<temp.step<<'\n';
return;
}
if(temp.x)
{
if(temp.x >= b - temp.y)
{
if(!book[temp.x-(b-temp.y)][b][temp.z])
{
book[temp.x-(b-temp.y)][b][temp.z] = true;
que[++tail] = {temp.x-(b-temp.y),b,temp.z,temp.step+1};
}
}
else
{
if(!book[0][temp.y+temp.x][temp.z])
{
book[0][temp.x+temp.y][temp.z] = true;
que[++tail] = {0,temp.x+temp.y,temp.z,temp.step+1};
}
}
if(temp.x >= c - temp.z)
{
if(!book[temp.x-(c-temp.z)][temp.y][c])
{
book[temp.x-(c-temp.z)][temp.y][c] = true;
que[++tail] = {temp.x-(c-temp.z),temp.y,c,temp.step+1};
}
}
else
{
if(!book[0][temp.y][temp.z+temp.x])
{
book[0][temp.y][temp.z+temp.x] = true;
que[++tail] = {0,temp.y,temp.z+temp.x,temp.step+1};
}
}
}
if(temp.y)
{
if(temp.y >= a - temp.x)
{
if(!book[a][temp.y-(a-temp.x)][temp.z])
{
book[a][temp.y-(a-temp.x)][temp.z] = true;
que[++tail] = {a,temp.y-(a-temp.x),temp.z,temp.step+1};
}
}
else
{
if(!book[temp.x+temp.y][0][temp.z])
{
book[temp.x+temp.y][0][temp.z] = true;
que[++tail] = {temp.x+temp.y,0,temp.z,temp.step+1};
}
}
if(temp.y >= c - temp.z)
{
if(!book[temp.x][temp.y-(c-temp.z)][c])
{
book[temp.x][temp.y-(c-temp.z)][c] = true;
que[++tail] = {temp.x,temp.y-(c-temp.z),c,temp.step+1};
}
}
else
{
if(!book[temp.x][0][temp.z+temp.y])
{
book[temp.x][0][temp.z+temp.y] = true;
que[++tail] = {temp.x,0,temp.z+temp.y,temp.step+1};
}
}
}
if(temp.z)
{
if(temp.z >= a - temp.x)
{
if(!book[a][temp.y][temp.z-(a-temp.x)])
{
book[a][temp.y][temp.z-(a-temp.x)] = true;
que[++tail] = {a,temp.y,temp.z-(a-temp.x),temp.step+1};
}
}
else
{
if(!book[temp.x+temp.z][temp.y][0])
{
book[temp.x+temp.z][temp.y][0] = true;
que[++tail] = {temp.x+temp.z,temp.y,0,temp.step+1};
}
}
if(temp.z >= b - temp.y)
{
if(!book[temp.x][b][temp.z-(b - temp.y)])
{
book[temp.x][b][temp.z-(b - temp.y)] = true;
que[++tail] = {temp.x,b,temp.z-(b - temp.y),temp.step+1};
}
}
else
{
if(!book[temp.x][temp.y+temp.z][0])
{
book[temp.x][temp.y+temp.z][0] = true;
que[++tail] = {temp.x,temp.z+temp.y,0,temp.step+1};
}
}
}
}
std::cout<<"NO\n";
}
int main()
{
// std::ios::sync_with_stdio(false);
// std::cin.tie(nullptr);
// std::cout.tie(nullptr);
while(std::cin>>a>>b>>c)
{
if(a==0&&b==0&&c==0)break;
for(int i = 1 ; i <= a ; i++)
for(int j = 1 ; j <= b ; j++)
for(int k = 1 ; k <= c ; k++)book[i][j][k] = false;
bfs();
}
}
#include<bits/stdc++.h>
typedef long long ll;
const int N = 1e2+10,M = 2e5+10,INF = 0x3f3f3f3f,mod = 1e9+7;
struct Node{
int b[3],step;
}que[N*N*N];
int a[3],pw[3];
bool book[N*N*N];
void bfs()
{
if(a[0]&1)
{
std::cout<<"NO\n";
return;
}
int tail = -1,head = 0;
que[++tail] = {a[0],0,0,0};
pw[0] = 1,pw[1] = 101,pw[2] = 101*101;
book[a[0]] = true;
while(tail >= head)
{
auto temp = que[head++];
if((temp.b[0]==a[0]/2)+(temp.b[1]==a[0]/2)+(temp.b[2]==a[0]/2)==2)
{
std::cout<<temp.step<<'\n';
return;
}
for(int i = 0 ; i <= 2 ; i++)
{
for(int j = 1 ; j <= 2 ; j++)
{
int x = i,y = (i+j)%3,z = (i+j+(j==1?1:-1))%3;
if(!temp.b[x])continue;
if(temp.b[x] >= (a[y]-temp.b[y]))
{
int state = (temp.b[x]-(a[y]-temp.b[y]))*pw[x]+a[y]*pw[y]+temp.b[z]*pw[z];
if(!book[state])
{
book[state] = true;
tail++;
que[tail].b[x] = temp.b[x]-(a[y]-temp.b[y]);
que[tail].b[y] = a[y];
que[tail].b[z] = temp.b[z];
que[tail].step = temp.step + 1;
}
}
else
{
int state = (temp.b[y]+temp.b[x])*pw[y]+temp.b[z]*pw[z];
if(!book[state])
{
book[state] = true;
tail++;
que[tail].b[x] = 0;
que[tail].b[y] = (temp.b[y]+temp.b[x]);
que[tail].b[z] = temp.b[z];
que[tail].step = temp.step + 1;
}
}
}
}
}
std::cout<<"NO\n";
}
int main()
{
// std::ios::sync_with_stdio(false);
// std::cin.tie(nullptr);
// std::cout.tie(nullptr);
while(std::cin>>a[0]>>a[1]>>a[2])
{
if(a[0]==0||a[1]==0||a[2]==0)break;
memset(book,false,sizeof book);
bfs();
}
}
