UVA 12657 Boxes in a Line

就是一个比较裸的双向链表的运用，只是处理的时候要注意，尤其是相邻的。

由于改BUG的时间较久，直接看注释就好了。

#include <stdio.h>
#include <string.h>

const int maxn = 1e5 + 10;
int left[maxn], right[maxn];
int flag;

//这个题目我们在模拟的时候，貌似我又发现一个问题，就是我们这个题目的逻辑貌似只能有一个
//就是你不能正过来是一个规律，倒过来是一个规律，他们必须是一个逻辑的
//就是你倒过来的时候，逻辑也应该是倒过来的
//当然，可能也是错误的
//--9/30 bug1:我数组遍历结果的时候，终止条件应该是0，不应该是n+1
//--9/30 bug2:就是我进入第一次反转的时候，这里有个bug,就是如果我们根据他的下表来的话，会有bug，不如根据个数来
//--9/30 bug3:left和right数组应该初始化
//--10/11 最终BUG：161行代码判断，相邻，有两种，xy和yx，一开始我只讨论了一种
//历时一周多，终于改出来了
int main()
{
    int n, m;
    long long num[maxn];
    int kases = 1;
    //freopen("f://duipai//data.txt","r",stdin);
    //freopen("f://duipai//outwa.txt","w",stdout);

    while(scanf("%d%d", &n, &m) == 2)
    {
        long long i;
        long long sum = 0;
        long long sum1 = 0;
        memset(left, 0, sizeof(left));
        memset(right, 0, sizeof(right));

        //本题的双向链表我们采用带头节点的来模拟
        for(i = 1; i <= n; i++)
        {
            num[i] = i;
            sum1 += i;
        }

        left[1] = 0;
        right[1] = 2;
        right[0] = 1;

        for(i = 2; i <= n - 1; i++)
        {
            left[i] = i - 1;
            right[i] = i + 1;
        }
        left[n] = n - 1;
        right[n] = n+1; //或者写0,这个具体还没有想好
        left[n+1] = n;

        int op, x, y;
        flag = 0;  //flag等于0说明这是正常序,flag等于1说明我们的顺序被我们倒过来了
        //还有一点我们要记住的是，就是我们的left,right存的不是下标，而是实实在在的数值
        for(i = 1; i <= m; i++)
        {
            scanf("%d", &op);
            int temp1, temp2,temp3, temp4;

            if(op == 1)
            {
                scanf("%d%d", &x, &y); //将x移到y的左边
                //right[x-1] = temp1; ???x-1是他妈的什么鬼?
                if(flag == 0)
                {
                    if(right[x] == y)
                    {
                        //printf("~~~~\n");
                        continue;
                    }

                    else
                    {
                        temp1 = right[x];
                        temp2 = left[x];
                        temp3 = left[y];
                        temp4 = right[y];

                        right[temp2] = temp1;
                        left[temp1] = temp2;
                        right[temp3] = x;
                        left[x] = temp3;
                        right[x] = y;
                        left[y] = x;
                    }
                }

                else if(flag == 1) //将x移动到y右边
                {
                    if(left[x] == y)
                        continue;
                    else
                    {
                        temp1 = left[x];
                        temp2 = right[x];
                        temp3 = left[y];
                        temp4 = right[y];

                        right[temp1] = temp2;
                        left[temp2] = temp1;
                        left[temp4] = x;
                        right[x] = temp4;
                        right[y] = x;
                        left[x] = y;
                    }
                }
            }

            else if(op == 2) //将x移动到y右边
            {
                scanf("%d%d", &x, &y);

                if(flag == 0)
                {
                    if(left[x] == y)
                        continue;

                    else
                    {
                        temp1 = left[x];
                        temp2 = right[x];
                        temp3 = left[y];
                        temp4 = right[y];

                        right[temp1] = temp2;
                        left[temp2] = temp1;
                        left[temp4] = x;
                        right[x] = temp4;
                        right[y] = x;
                        left[x] = y;
                    }
                }

                else if(flag == 1) //将x移动到y的左边
                {
                    if(right[x] == y)
                        continue;
                    else
                    {
                        temp1 = right[x];
                        temp2 = left[x];
                        temp3 = left[y];
                           temp4 = right[y];

                        right[temp2] = temp1;
                        left[temp1] = temp2;
                        right[temp3] = x;
                        left[x] = temp3;
                        right[x] = y;
                        left[y] = x;
                    }
                }
            }

            else if(op == 3)
            {
                scanf("%d%d", &x, &y); //意思就是我们x和y互相交换位置
                //出现bug的原因是相邻的没有解决
                if(flag == 0)
                {
                    if(right[x] != y && left[y] != x && left[x] != y && right[y] != x)
                    {
                        temp1 = left[x];
                        temp2 = right[x];
                        temp3 = left[y];
                        temp4 = right[y];

                        right[temp1] = y;
                        left[y] = temp1;
                        right[y] = temp2;
                        left[temp2] = y;

                        right[temp3] = x;
                        left[x] = temp3;
                        right[x] = temp4;
                        left[temp4] = x;
                    }

                    else
                    {
                        if(right[x] == y)
                        {
                            temp1 = left[x];
                            temp2 = right[y];
                            right[temp1] = y;
                            left[y] = temp1;
                            right[y] = x;
                            left[x] = y;
                            right[x] = temp2;
                            left[temp2] = x;
                            continue;
                        }

                        else if(left[x] == y)
                        {
                            temp1 = left[y];
                            temp2 = right[x];
                            right[temp1] = x;
                            left[x] = temp1;
                            right[x] = y;
                            left[y] = x;
                            right[y] = temp2;
                            left[temp2] = y;
                        }
                    }
                }

                else if( flag == 1 )
                {
                    if(right[x] != y && right[y] != x)
                    {
                        temp1 = left[x];    //right[x]
                        temp2 = right[x];   //left[x]
                        temp3 = left[y];    //right[y]
                        temp4 = right[y];    //left[y]

                        left[temp2] = y;
                        right[y] = temp2;
                        left[y] = temp1;
                        right[temp1] = y;

                        left[x] = temp3;
                        right[temp3] = x;
                        right[x] = temp4;
                        left[temp4] = x;
                    }

                    else
                    {
                        if(right[x] == y)
                        {
                            temp1 = left[x];
                            temp2 = right[y];
                            right[temp1] = y;
                            left[y] = temp1;
                            right[y] = x;
                            left[x] = y;
                            right[x] = temp2;
                            left[temp2] = x;
                            continue;
                        }

                        else if(left[x] == y)
                        {
                            temp1 = left[y];
                            temp2 = right[x];
                            right[temp1] = x;
                            left[x] = temp1;
                            right[x] = y;
                            left[y] = x;
                            right[y] = temp2;
                            left[temp2] = y;
                        }
                    }
                }

            }

            else if(op == 4)
            {
                flag = !flag;

                if(flag == 1)
                {
                    temp1 = left[n+1];
                    temp2 = right[0];
                    left[0] = temp1;
                    right[temp1] = 0;
                    right[n+1] = temp2;
                    left[temp2] = n + 1;
                }

                else if(flag == 0)
                {
                    temp1 = left[0];
                    temp2 = right[n+1];
                    right[0] = temp2;
                    left[temp2] = 0;
                    right[temp1] = n+1;
                    left[n+1] = temp1;

                }
            }
        }

        if(flag == 0) //正常的顺序
        {
            i = right[0];
            long long j = left[n+1];
            //printf("数组的开头 %lld~~~~\n", i);
            //printf("数组的结尾 %lld~~~~\n", j);
            //printf("数组奇数位的数字: ");
            if(n % 2 == 0) // n是偶数
            {
                int k;
                for(k = 1; k <= n / 2;k++)
                {

                    //printf("%lld ", i);
                    sum += i;
                    i = right[i];
                    i = right[i];
                }
            }
            else if(n % 2 == 1)
            {
                int k;
                for(k = 1; k <= (n+1) / 2; k++)
                {
                    //printf("%lld ", i);
                    sum += i;
                    i = right[i];
                    i = right[i];
                }
            }
            //printf("\n");

            printf("Case %d: %lld\n", kases++, sum);
        }

        else if(flag == 1) //倒过来的顺序
        {
            i = left[0];
            long long j = right[n+1];
            //printf("数组的开头 %lld~~~~\n", i);
            //printf("数组的结尾 %lld~~~~\n", j);
            //printf("数组奇数位的数字: ");
            //printf("~~~%lld\n", left[n+1]);
            if(n % 2 == 0)
            {
                int k;
                for(k = 1; k <= n / 2; k++)
                {
                    //printf("%lld ", i);
                    sum += i;
                    i = left[i];
                    i = left[i];
                }
            }

            else if(n % 2 == 1)
            {
                int k;
                for(k = 1; k <= (n+1) / 2; k++)
                {
                    //printf("%lld ", i);
                    sum += i;
                    i = left[i];
                    i = left[i];
                }
            }
            //printf("\n");
            printf("Case %d: %lld\n", kases++, sum);
        }
    }
    return 0;
}