HDU6165 FFF at Valentine(深搜dfs,2017 HDU多校联赛 第9场)

题目：

FFF at Valentine

Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 456    Accepted Submission(s): 224

Problem Description

At Valentine's eve, Shylock and Lucar were enjoying their time as any other couples. Suddenly, LSH, Boss of FFF Group caught both of them, and locked them into two separate cells of the jail randomly. But as the saying goes: There is always a way out , the lovers made a bet with LSH: if either of them can reach the cell of the other one, then LSH has to let them go.
The jail is formed of several cells and each cell has some special portals connect to a specific cell. One can be transported to the connected cell by the portal, but be transported back is impossible. There will not be a portal connecting a cell and itself, and since the cost of a portal is pretty expensive, LSH would not tolerate the fact that two portals connect exactly the same two cells.
As an enthusiastic person of the FFF group, YOU are quit curious about whether the lovers can survive or not. So you get a map of the jail and decide to figure it out.

 

Input

∙Input starts with an integer T (T≤120), denoting the number of test cases.
∙For each case,
First line is two number n and m, the total number of cells and portals in the jail.(2≤n≤1000,m≤6000)
Then next m lines each contains two integer u and v, which indicates a portal from u to v.

 

Output

If the couple can survive, print “I love you my love and our love save us!”
Otherwise, print “Light my fire!”

 

Sample Input

35 51 22 32 43 54 53 31 22 33 15 51 22 33 13 44 5

 

Sample Output

Light my fire!I love you my love and our love save us!I love you my love and our love save us!

 

Source

2017 Multi-University Training Contest - Team 9

思路：

题目给了有向图n个点m条边，问任意两个点能否从一方到达另一方（从a到b或者从b到a都行），做法就是用vector存边暴搜。。

代码：

#include <cstdio>#include <cstring>#include <cctype>#include <string>#include <set>#include <iostream>#include <stack>#include <cmath>#include <queue>#include <vector>#include <algorithm>#define mem(a,b) memset(a,b,sizeof(a))#define inf 0x3f3f3f3f#define mod 1000007#define ll long longusing namespace std;const int N=1e3+5;vector<int>f[N];int vis[N],dis[N][N];int n,m,pos;void dfs(int u){vis[u]=1;dis[pos][u]=1;for(int i=0; i<f[u].size(); i++){int v=f[u][i];if(!vis[v])dfs(v);}}int main(){int t;scanf("%d",&t);while(t--){scanf("%d%d",&n,&m);for(int i=1; i<=n; i++)f[i].clear();int a,b;for(int i=1; i<=m; i++){scanf("%d%d",&a,&b);f[a].push_back(b);}mem(dis,0);int flag=1;for(int i=1; i<=n; i++){mem(vis,0);pos=i;dfs(i);}for(int i=1; i<=n; i++)for(int j=i+1; j<=n; j++)if(!dis[i][j]&&!dis[j][i]){flag=0;break;}if(flag)puts("I love you my love and our love save us!");elseputs("Light my fire!");}return 0;}