POJ 1094Sorting It All Out（拓扑排序）

来源：互联网发布：网络背景音乐歌曲链接编辑：程序博客网时间：2024/04/20 22:46
题目地址：http://poj.org/problem?id=1094
这个题改了一下午。。代码越改越挫。。凑活着看吧。。
#include <iostream>#include <stdio.h>#include <string.h>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <algorithm>using namespace std;int d[30], head[30], n, cnt, a[30], num, s, hash1[30], y;struct node{    int u, v, w;    int next;} edge[100000];void add(int u, int v, int w){    edge[cnt].v=v;    edge[cnt].w=w;    edge[cnt].next=head[u];    head[u]=cnt++;}int tops(){    int i, j, flag=0, x, u, z=0;    s=0;    while(1)    {        x=0;        for(j=1; j<=n; j++)        {            if(hash1[j]&&d[j]==0)            {                a[s]=j;                u=j;                d[j]--;                x++;                s++;            }        }        if(x==0&&s==n)        {            if(z==0)            flag=1;            break;        }        if(x==0&&s<y)        {            flag=2;            break;        }        if(x==0&&s==y)        {            break;        }        if(x>=1)        {            if(x>1)                z=1;            for(i=0; i<s; i++)            {                for(j=head[a[i]]; j!=-1; j=edge[j].next)                {                    if(edge[j].w==1)                    {                        edge[j].w--;                        d[edge[j].v]--;                    }                }            }        }    }    return flag;}int main(){    int m, i, flag, k, b[1000], dd[1000], yy;    char c1, c2, c;    //freopen("1.txt","r",stdin);    while(scanf("%d%d",&n,&m)!=EOF&&n&&m)    {        cnt=0;        num=0;        flag=0;        memset(hash1,0,sizeof(hash1));        while(m--)        {            cnt=0;            num++;            getchar();            scanf("%c%c%c",&c1,&c,&c2);            //printf("--1%c %c\n",c1,c2);            b[num-1]=c1-'A'+1;            //printf("--2%c %c\n",c1,c2);            dd[num-1]=c2-'A'+1;            //printf("--3%c %c\n",c1,c2);            memset(head,-1,sizeof(head));            memset(d,0,sizeof(d));            //printf("--4%c %c\n",c1,c2);            for(i=0; i<num-1; i++)            {                d[dd[i]]++;                add(b[i],dd[i],1);            }            d[c2-'A'+1]++;            add(c1-'A'+1,c2-'A'+1,1);            hash1[c1-'A'+1]++;            hash1[c2-'A'+1]++;            y=0;            for(i=1; i<=n; i++)            {                if(hash1[i])                {                    y++;                }            }            if(!flag)            {                yy=tops();                if(yy==1)                {                    k=num;                    flag=1;                }                else if(yy==2)                {                    k=num;                    flag=2;                }            }        }        if(flag==0)            printf("Sorted sequence cannot be determined.\n");        else if(flag==1)        {            printf("Sorted sequence determined after %d relations: ",k);            for(i=0; i<n; i++)                printf("%c",a[i]+'A'-1);            printf(".\n");        }        else            printf("Inconsistency found after %d relations.\n",k);    }    return 0;}
0 0