Gap HDU - 1067 BFS

最新推荐文章于 2020-12-14 08:13:45 发布

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本文介绍了一种使用暴力广度优先搜索（BFS）结合Map进行状态判重的方法，通过具体实现展示了如何解决特定问题。文章包括了完整的C++代码示例，并详细解释了其工作原理。

暴力bfs + map判重

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <cstring>
#include <queue>
#include <cmath>
#include <map>

using namespace std;

struct node
{
    char a[33];
    int t;
}s;

char e[33] = {11, 12, 13, 14, 15, 16, 17, 1, 21, 22, 23, 24, 25, 26, 27, 1,
    31, 32, 33, 34, 35, 36, 37, 1, 41, 42, 43, 44, 45, 46, 47, 1};

void print(node t)
{
    for (int k = 0; k < 32; k++)
    {
        if (k % 8 == 0)
            printf("\n");
        printf("%d ", t.a[k]);
    }
}

int bfs()
{
    queue<node> q;
    s.t = 0;
    q.push(s);
    map<string, int> ma;
    int cnt = 0;
    ma[s.a] = ++cnt;
    if (ma[s.a] == ma[e])
        return 0;
    ma[e] = ++cnt;
    while (!q.empty())
    {
        node cur = q.front(); q.pop();
        for (int i = 0; i < 32; i++)
            if (cur.a[i] == 1 && cur.a[i - 1] != 1 && cur.a[i - 1] % 10 != 7)
            {
                node tmp = cur;
                int val = cur.a[i - 1] + 1;
                for (int k = 0; k < 32; k++)
                    if (tmp.a[k] == val)
                    {
                        tmp.a[k] = 1;
                        tmp.a[i] = val;
                        break;
                    }
                tmp.t++;
                if (ma[tmp.a] == 2)
                    return tmp.t;
                if (ma[tmp.a] == 0)
                {
                    ma[tmp.a] = ++cnt;
                    q.push(tmp);
                }
            }
    }

    return -1;
}

int main()
{
    int T;
    scanf("%d", &T);
    while (T--)
    {
        int k = 0, tmp;
        for (int i = 1; i <= 4; i++)
        {
            s.a[k++] = 1 + 10 * i;
            for (int j = 1; j <= 7; j++)
            {
                scanf("%d", &tmp);
                s.a[k] = tmp;
                if (tmp % 10 == 1)
                    s.a[k] = 1;
                k++;
            }
        }
        printf("%d\n", bfs());
    }


    return 0;
}