HDU1281 board game (binary match + find the necessary points)

Test instructions

Here's a map of N*m and a point on the K map where you can put your car.

Let you find out how many cars and which points are necessary (no match number will be reduced)

Ideas:

Hungary asks for the maximum match, and then one deletes the matching points to match,

If the number of matches is reduced after the point is deleted, this point is necessary

Code:

Starting with Vector to remember the point parameters to delete the trouble

/************************************************//author:d evil//created TIME:2016/5/10 17:22:52//*********** ************************************* */#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<vector>#include<queue>#include<Set>#include<map>#include<string>#include<cmath>#include<stdlib.h>using namespacestd;Const intn= the; Vector<int>Eg[n];intLink[n],used[n],dx;BOOLVis[n];BOOLDfsintUintf) {     for(intI=0; I<eg[u].size (); i++)    {        intv=Eg[u][i]; if(!F&AMP;&AMP;U==DX&AMP;&AMP;V==USED[DX])Continue; if(!Vis[v]) {Vis[v]=1; if(link[v]==-1||DFS (LINK[V],F)) {Link[v]=u; if(f) used[u]=v; return 1; }        }    }    return 0;}intMain () {//freopen ("In.txt", "R", stdin);    intn,m,k,x,y,cas=0;  while(~SCANF ("%d%d%d",&n,&m,&k) {memset (link),-1,sizeof(link));  for(intI=1; i<= -; i++) eg[i].clear (); memset (Used,0,sizeof(used));  while(k--) {scanf ("%d%d",&x,&y);        Eg[x].push_back (y); }        intMa=0, ans=0;  for(intI=1; i<=n;i++) {memset (Vis,0,sizeof(VIS)); Ma+=dfs (I,1); }         for(intI=1; i<=n;i++)        {            if(Used[i]) {memset (link),-1,sizeof(link)); intnow=0; DX=i;  for(intj=1; j<=n;j++) {memset (Vis,0,sizeof(VIS)); now+=dfs (J,0); }                if(NOW!=MA) ans++; }} printf ("Board%d has%d important blanks for%d chessmen.\n",++Cas,ans,ma); }    return 0;}

And then simply write with the adjacency matrix.

/************************************************//author:d evil//created TIME:2016/5/10 17:23:18//*********** ************************************* */#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<vector>#include<queue>#include<Set>#include<map>#include<string>#include<cmath>#include<stdlib.h>using namespacestd;Const intn= the;intlink[n],used[n],n,m,k;BOOLMp[n][n],vis[n];BOOLDfsintUintf) {     for(intI=1; i<=m;i++)    {        if(mp[u][i]&&!Vis[i]) {Vis[i]=1; if(link[i]==-1||DFS (LINK[I],F)) {Link[i]=u; if(f) used[u]=i; return 1; }        }    }    return 0;}intMain () {//freopen ("In.txt", "R", stdin);    intx,y,cas=0;  while(~SCANF ("%d%d%d",&n,&m,&k) {memset (link),-1,sizeof(link)); Memset (MP,0,sizeof(MP)); memset (Used,0,sizeof(used));  while(k--) {scanf ("%d%d",&x,&y); Mp[x][y]=1; }        intMa=0, ans=0;  for(intI=1; i<=n;i++) {memset (Vis,0,sizeof(VIS)); Ma+=dfs (I,1); }         for(intI=1; i<=n;i++)        {            if(Used[i]) {memset (link),-1,sizeof(link)); intnow=0; Mp[i][used[i]]=0;  for(intj=1; j<=n;j++) {memset (Vis,0,sizeof(VIS)); now+=dfs (J,0); } Mp[i][used[i]]=1; if(NOW!=MA) ans++; }} printf ("Board%d has%d important blanks for%d chessmen.\n",++Cas,ans,ma); }    return 0;}

HDU1281 board game (binary match + find the necessary points)