一开始以为这题是二分图的匹配,然后用匈牙利做,TLE,然后用HK 做, TLE。。。
最后发现是用网络流做的,而且要将100000个点压缩, 因为每个点的可能选择情况有2^10 ,所以根据这个可以将图压缩成1000*10大小的图,这样用网络流就没有压力了...
网络流建模很重要.!
Escape
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 2483 Accepted Submission(s): 687
Problem Description
2012 If this is the end of the world how to do? I do not know how. But now scientists have found that some stars, who can live, but some people do not fit to live some of the planet. Now scientists want your help, is to determine what all of people can live in these planets.
Input
More set of test data, the beginning of each data is n (1 <= n <= 100000), m (1 <= m <= 10) n indicate there n people on the earth, m representatives m planet, planet and people labels are from 0. Here are n lines, each line represents a suitable living conditions of people, each row has m digits, the ith digits is 1, said that a person is fit to live in the ith-planet, or is 0 for this person is not suitable for living in the ith planet. The last line has m digits, the ith digit ai indicates the ith planet can contain ai people most.. 0 <= ai <= 100000
Output
Determine whether all people can live up to these stars If you can output YES, otherwise output NO.
Sample Input
1 1 1 1 2 2 1 0 1 0 1 1
Sample Output
YES NO
Source
Recommend
lcy
Escape
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 2483 Accepted Submission(s): 687
Problem Description
2012 If this is the end of the world how to do? I do not know how. But now scientists have found that some stars, who can live, but some people do not fit to live some of the planet. Now scientists want your help, is to determine what all of people can live in these planets.
Input
More set of test data, the beginning of each data is n (1 <= n <= 100000), m (1 <= m <= 10) n indicate there n people on the earth, m representatives m planet, planet and people labels are from 0. Here are n lines, each line represents a suitable living conditions of people, each row has m digits, the ith digits is 1, said that a person is fit to live in the ith-planet, or is 0 for this person is not suitable for living in the ith planet. The last line has m digits, the ith digit ai indicates the ith planet can contain ai people most.. 0 <= ai <= 100000
Output
Determine whether all people can live up to these stars If you can output YES, otherwise output NO.
Sample Input
1 1 1 1 2 2 1 0 1 0 1 1
Sample Output
YES NO
Source
Recommend
lcy
#include#include #include using namespace std;#define N 100100#define K 1111#define INF 0x3fffffffstruct node{ int to,next,w;}edge[N];int cnt,pre[2200];int n,m;int s,t;int g[N][11];int save[2200];int tt;int gap[2200],lv[2200];void add_edge(int u,int v,int w){ edge[cnt].to=v; edge[cnt].w=w; edge[cnt].next=pre[u]; pre[u]=cnt++;}int sdfs(int k,int w){ if(k==t) return w; int f=0; int mi=tt; for(int p=pre[k];p!=-1;p=edge[p].next) { int v=edge[p].to; if(edge[p].w!=0) { if( lv[k]==lv[v]+1 ) { int tmp=sdfs(v,min(edge[p].w,w-f)); f += tmp; edge[p].w -= tmp; edge[p^1].w += tmp; if( f==w || lv[s]==tt ) return f; } if(lv[v] < mi) mi=lv[v]; } } if(f==0) { gap[lv[k]]--; if( gap[lv[k]]==0 ) { lv[s]=tt; return 0; } lv[k]=mi+1; gap[lv[k]]++; } return f;}int sap(){ int sum=0; tt=t+1; memset(gap,0,sizeof(gap)); memset(lv,0,sizeof(lv)); gap[0]=tt; while(lv[s] >= 1; } } } for(int i=1;i<=m;i++) { int tmp; scanf("%d",&tmp); add_edge(K+i,t,tmp); add_edge(t,K+i,0); } if(sap()==n) printf("YES\n"); else printf("NO\n"); } return 0;}