POJ 1364 King(差分约束)

题目链接

根据连续的和建图，然后判断是否有负环。注意细节，加上超级源点后，有n+1个点。忘了初始化了，让我WA了N次啊。

#include <iostream>

#include <cstdio>

#include <cmath>

#include <cstring>

#include <queue>

#include <cstdlib>

#include <ctime>

#include <map>

using namespace std;

#define N 1001

struct node

{

    int u,v,w,next;

}edge[N];

int first[N],d[N];

int t;

void add(int u,int v,int w)

{

    edge[t].u = u;

    edge[t].v = v;

    edge[t].w = w;

    edge[t].next = first[u];

    first[u] = t;

    t ++;

}

void CL()

{

    t = 1;

    memset(first,-1,sizeof(first));

}

int main()

{

    int n,m,x,y,w,i,flag,j;

    int u,v;

    char ch[10];

    while(scanf("%d",&n)!=EOF)

    {

        if(n == 0)

        break;

        scanf("%d",&m);

        CL();

        for(i = 1;i <= m;i ++)

        {

            scanf("%d%d%s%d",&x,&y,ch,&w);

            if(ch[0] == 'g')

            {

                add(x-1,x+y,w+1);

            }

            else

            {

                add(x+y,x-1,1-w);

            }

        }

        memset(d,0,sizeof(d));

        for(i = 1;i <= n+1;i ++)

        {

            flag = 1;

            for(j = 1;j < t;j ++)

            {

                u = edge[j].u;

                v = edge[j].v;

                if(d[v] < d[u] + edge[j].w)

                {

                    d[v] = d[u] + edge[j].w;

                    flag = 0;

                }

            }

            if(flag) break;

        }

        if(flag == 0)

        printf("successful conspiracy\n");

        else

        printf("lamentable kingdom\n");

    }

    return 0;

}