ZOJ 2770 Burn the Linked Camp(spfa&&bellman)

//差分约束  >=求最长路径 <=求最短路径   结果都一样
//spfa
#include<stdio.h>
#include<string.h>
#include<limits.h>
#include<queue>
using namespace std;
#define N 1010
#define M 1010*1010//注意边和点集的数组大小
struct edge
{
    int to,value,next;
};
struct edge edges[M];
int heads[N],len=0;
int dis[N];
int addedge(int u,int v,int w)
{
    edges[len].to=v,edges[len].value=w,edges[len].next=heads[u];
    heads[u]=len++;
    return 0;
}
int n,m;

int spfa(int v)
{
    queue<int> q;
    int inqueue[N];
    memset(inqueue,0,sizeof(inqueue)),inqueue[v]=1;
    q.push(v);
    for(int i=0;i<=n;i++) dis[i]=INT_MIN;
    dis[v]=0;
    int times[N];
    memset(times,0,sizeof(times)),times[v]=1;
    int temp=0;
    while(!q.empty()){
        int x=q.front();
        q.pop();
        inqueue[x]=0;

        for(int i=heads[x];i!=-1;i=edges[i].next){
            int to=edges[i].to,value=edges[i].value;
            if(value+dis[x]>dis[to]){
                dis[to]=value+dis[x];
                
                if(!inqueue[to]){  //注意已经在队列里面的不用再加入队列
                    inqueue[to]=1,q.push(to);
                    times[to]++;
                    if(times[x]>n){
                        return -1;//返回值有可能是0 不能将0作为区别的标记
                        
                    }
                    
                }
            }
        }
    }
    return dis[n];
}
int main(void)
{
    
    int i,num;
    while(scanf("%d%d",&n,&m)!=EOF){
        len=0;
        memset(heads,-1,sizeof(heads));
        for(i=1;i<=n;i++){
            scanf("%d",&num);
            addedge(i,i-1,-num);  
            addedge(0,i,0);  
        }
        for(i=1;i<=m;i++){
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            addedge(u-1,v,w);
        }
        
        int h=spfa(0);
        if(h!=-1) printf("%d\n",h);
        else printf("Bad Estimations\n");


    }
    return 0;
}
//bellman

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

using namespace std;
#define INF 2000000000
int u[12005],v[12005],w[12005],n,m,total,d[1005];
void Edge(int s,int e,int val){
	u[total]=s;
	v[total]=e;
	w[total++]=val;
}
int Bellman(){
	int i,e;
	for(i=1;i<=n;i++) d[i]=-INF;
	d[0]=0;
	for(i=1;i<=n;i++){
		for(e=0;e<total;e++){
			if(d[v[e]]<d[u[e]]+w[e])	
				d[v[e]]=d[u[e]]+w[e];
		}
	}
	int ans=d[n];
	for(e=0;e<total;e++)
		if(d[v[e]]<d[u[e]]+w[e]) ans=-1;
	return ans;
}
int main(){
	int a,b,c,cnt,i;
	while(scanf("%d%d",&n,&m)!=EOF){
		total=0;
		for(i=1;i<=n;i++){
			scanf("%d",&c);
			Edge(0,i,0);
			Edge(i,i-1,-c);
		}
		for(i=0;i<m;i++){
			scanf("%d%d%d",&a,&b,&c);
			Edge(a-1,b,c);
		}
		
		cnt=Bellman();
		for(i=0;i<n;i++) printf("%d ",d[i]);
		puts("");
		if(cnt==-1) cout<<"Bad Estimations\n";
		else cout<<cnt<<"\n";
	}
	return 0;
}