https://cn.vjudge.net/problem/POJ-3414
#include <iostream>
#include <cstdio>
#include <queue>
#include <cstring>
#include <cstdlib>
using namespace std;
struct node
{
int x, y;
int step;
char st[110][110];
} t, f;
int visit[110][110];
void bfs(int a, int b, int c)
{
queue <node> q;
memset(visit, 0, sizeof(visit));
t.x = a;
t.y = 0;
t.step = 1;
strcpy(t.st[1],"FILL(1)");
q.push(t);
t.x = 0;
t.y = b;
t.step = 1;
strcpy(t.st[1],"FILL(2)");
q.push(t);
visit[0][0] = 1;
while(!q.empty())
{
f = q.front();
q.pop();
if(f.x==c||f.y==c)
{
printf("%d\n", f.step);
for(int i=1; i<=f.step; i++)
{
printf("%s\n", f.st[i]);
}
return;
}
t = f;
t.x = a;
t.y = f.y;
t.step++；
strcpy(t.st[t.step], "FILL(1)");
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
t = f;
t.x = f.x;
t.y = b;
t.step++;
strcpy(t.st[t.step], "FILL(2)");
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
t = f;
t.x = 0;
t.y = f.y;
t.step++;
strcpy(t.st[t.step], "DROP(1)");
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
t = f;
t.x = f.x;
t.y = 0;
t.step++;
strcpy(t.st[t.step], "DROP(2)");
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
if(f.x+f.y>a)
{
t = f;
t.x = a;
t.y = f.x+f.y-a;
t.step++;
strcpy(t.st[t.step], "POUR(2,1)");
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
}
else
{
t = f;
t.x = f.x+f.y;
t.y = 0;
t.step++;
strcpy(t.st[t.step], "POUR(2,1)");
}
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
if(f.x+f.y>b)
{
t = f;
t.x = f.x+f.y-b;
t.y = b;
t.step++;
strcpy(t.st[t.step], "$$POUR(1,2)");
}
else
{
t = f;
t.x = 0;
t.y = f.x+f.y;
t.step++;
strcpy(t.st[t.step], "##POUR(1,2)");
}
if(visit[t.x][t.y]==0)
{
visit[t.x][t.y] = 1;
q.push(t);
}
}
printf("impossible\n");
return ;
}
int main()
{
int a, b, c;
scanf("%d%d%d", &a, &b, &c);
bfs(a, b, c);
return 0;
}