2718: [VIOLET 4] graduation trip time limit: 10 sec memory limit: 128 MB
Submit: 229 solved: 126
[Submit] [Status] Description
Input
Output
Maximum number of scenic spots
Sample input7 6
1 2
2 3
5 4
4 3
3 6
6 7
Sample output2
Hint
Source
Ctsc2008 River & Ural 1533. Fat Hobbits
Question: Same as the previous Code:
1 #include<cstdio> 2 #include<cstdlib> 3 #include<cmath> 4 #include<cstring> 5 #include<algorithm> 6 #include<iostream> 7 #include<vector> 8 #include<map> 9 #include<set>10 #include<queue>11 #define inf 100000000012 #define maxn 11013 #define maxm 500+10014 #define eps 1e-1015 #define ll long long16 #define pa pair<int,int>17 using namespace std;18 inline int read()19 {20 int x=0,f=1;char ch=getchar();21 while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}22 while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}23 return x*f;24 }25 int p[maxn],n,m,f[maxn][maxn];26 bool v[maxn];27 bool find(int x)28 {29 for(int i=1;i<=n;i++)30 if (f[x][i])31 if(!v[i])32 {33 v[i]=1;34 if(!p[i]||find(p[i]))35 {36 p[i]=x;37 return 1;38 }39 }40 return 0; 41 }42 int main()43 {44 freopen("input.txt","r",stdin);45 freopen("output.txt","w",stdout);46 n=read();m=read();47 int x,y;48 while(m--)x=read(),y=read(),f[x][y]=1;49 for(int k=1;k<=n;k++)50 for(int i=1;i<=n;i++)51 for(int j=1;j<=n;j++)52 f[i][j]=f[i][j]||(f[i][k]&&f[k][j]);53 int ans=0; 54 for(int i=1;i<=n;i++)55 {56 memset(v,0,sizeof(v));57 if(find(i))ans++;58 } 59 printf("%d\n",n-ans);60 return 0; 61 }
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Bzoj2718: [VIOLET 4] Graduation Trip