HDU

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1495

Sample Input
7 4 3
4 1 3
0 0 0
Sample Output
NO
3

分析：虽然这里是作为搜索题出现的，但同时也算是道数学规律题吧，这写出来可就容易多了

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <stdlib.h>
#include<queue>
#include<math.h>
using namespace std;

#define N 1250
#define maxn 115200
#define INF 0x3f3f3f3f7 4 3

int gcd(int a,int b)
{
    return b==0?a:gcd(b,a%b);
}

int main()
{
    int s,n,m,t;

    while(scanf("%d%d%d",&s,&n,&m),n+m+s)
    {
        if(n<m)
            t=n,n=m,m=t;
        s/=gcd(n,m);

        if(s%2 != 0)
            printf("NO
");
        else
            printf("%d
",s-1);
    }
    return 0;
}

附上学长广搜代码：

共6种倒法，开个数组用下标表示~

#include<stdio.h>
#include<string.h>
using namespace std;

const int maxn = 105;
const int oo = 0xfffffff;

struct node{int cup[3], step;};
node q;
int Full[3];
int dir[6][2] = { {0,1},{0,2},{1,0},{1,2},{2,0},{2,1} };
int v[maxn][maxn][maxn];

void Turn(int &a, int &b, int FullB)//把瓶子a里面的水倒入瓶子B
{
    if(a+b <= FullB)
        b += a, a=0;
    else
    {
        a -= (FullB-b);
        b = FullB;
    }
}
int OK(node s)//判断是否已经分好
{
    if(s.cup[0]+s.cup[1] == Full[0] && s.cup[0] == s.cup[1])
        return 1;
    if(s.cup[0]+s.cup[2] == Full[0] && s.cup[0] == s.cup[2])
        return 1;
    if(s.cup[1]+s.cup[2] == Full[0] && s.cup[1] == s.cup[2])
        return 1;

    return 0;
}
int Bfs(node s)
{
    queue<node> Q;
    Q.push(s);

    while(Q.size())
    {
        s = Q.front();Q.pop();

        if(OK(s))
            return s.step;

        for(int i=0; i<6; i++)
        {
            q = s;
            Turn(q.cup[ dir[i][0] ], q.cup[ dir[i][1] ], Full[dir[i][1]]);

            if(v[q.cup[0]][q.cup[1]][q.cup[2]] == 0)
            {
                v[q.cup[0]][q.cup[1]][q.cup[2]] = 1;
                q.step++;
                Q.push(q);
            }
        }
    }

    return -1;
}

int main()
{
    node s;

    while(scanf("%d%d%d", &Full[0], &Full[1], &Full[2]), Full[0]+Full[1]+Full[2])
    {
        memset(v, 0, sizeof(v));

        s.cup[0] = Full[0];
        s.cup[1]=s.cup[2]=s.step=0;
        int ans = Bfs(s);

        if(ans == -1)
            printf("NO
");
        else
            printf("%d
", ans);
    }

    return 0;
}