poj 1724ROADS（bfs和dfs做法）

/*
dfs比较好想，就是测试数据的问题，导致在遍历边的时候要倒着遍历才过！
*/
#include<iostream> 
#include<cstdio>
#include<cstring>
#include<vector>
#include<algorithm>
#define Max 0x3f3f3f3f
using namespace std;

struct node{
   int D;
   int L, T;
   node(int D, int L, int T){
      this->D=D;
      this->L=L;
      this->T=T;
   }
   node(){
   }
};

node v[105][1000];
int cnt[105];
int vis[105];

int maxCost, R, N, S, D, L, T;
int cost, dist;

void dfs(int cur, int d, int c){
   int i;
   if(cur == N){
       if(dist>d){
          dist=d;
          if(cost>c)  cost=c;
       }
       return ;
   }
   for(i=cnt[cur]-1; i>=0; --i)
      if(!vis[v[cur][i].D] &&  c+v[cur][i].T<=maxCost && d+v[cur][i].L<dist){
         vis[v[cur][i].D]=1;
         dfs(v[cur][i].D, d+v[cur][i].L, c+v[cur][i].T);
         vis[v[cur][i].D]=0;
      }
}

int main(){
   while(scanf("%d", &maxCost)!=EOF){
       scanf("%d%d", &N, &R);
       memset(cnt, 0, sizeof(cnt));
       while(R--){
          scanf("%d%d%d%d", &S, &D, &L, &T);
          v[S][cnt[S]++]=node(D, L, T);
       }
       cost=dist=Max;
       memset(vis, 0, sizeof(vis));
       dfs(1, 0, 0);
       if(cost<=maxCost)
          printf("%d
", dist);
       else printf("-1
");
   }
   return 0;
}

/*
  spfa + 01背包 
  dist[next][j]=min(dist[cur][j-v[cur][i].T]+v[cur][i].L) j={v[cur][i].T。。。maxCost}
  一维数组表示的是城市节点，二维表示的当前费用
  dist[i][j]表示经过i城市，费用为j时总的路径长度！ 
*/
#include<iostream> 
#include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<algorithm>
#define Max 0x3f3f3f3f
using namespace std;

struct node{
   int D;
   int L, T;
   node(int D, int L, int T){
      this->D=D;
      this->L=L;
      this->T=T;
   }
   node(){
   }
};

node v[105][1000];
int cnt[105];
int dist[105][10005];
int vis[105];
queue<int>q;
int maxCost, R, N, S, D, L, T;

int spfa(){
   int i;
   while(!q.empty()){
       int cur = q.front();
       q.pop();
       vis[cur]=0;
       for(i=0; i<cnt[cur]; ++i){
           int next=v[cur][i].D;
           for(int j=v[cur][i].T; j<=maxCost; ++j)
              if(dist[next][j]>dist[cur][j-v[cur][i].T]+v[cur][i].L){
                 dist[next][j]=dist[cur][j-v[cur][i].T]+v[cur][i].L;
                 if(!vis[next]){
                   vis[next]=1;
                   q.push(next);
                 }
             }
       }
   }
}

void bfs(int cur){
   q.push(1);
   memset(dist, 0x3f, sizeof(dist));
   for(int i=0; i<105; ++i)
      dist[1][i]=0;
   vis[1]=1;
   spfa();
}

int main(){
   while(scanf("%d", &maxCost)!=EOF){
       scanf("%d%d", &N, &R);
       memset(cnt, 0, sizeof(cnt));
       while(R--){
          scanf("%d%d%d%d", &S, &D, &L, &T);
          v[S][cnt[S]++]=node(D, L, T);
       }
       memset(vis, 0, sizeof(vis));
       bfs(1);
       int minDist=Max;
       for(int i=1; i<=maxCost; ++i)
          if(minDist>dist[N][i])
              minDist=dist[N][i];
       if(minDist!=Max)
          printf("%d
", minDist);
       else printf("-1
");
   }
   return 0;
}