HDU1507 Uncle Tom's inherited land* binary map matching Hungarian algorithm black and white dyeing

Original link http://www.cnblogs.com/zhouzhendong/p/8254062.html

Topic Portal-HDU1507Test Instructions Summary

There is a n*m chess board, some of the points are obsolete.

Now let you use the 1*2 rectangle to cover all the non-scrap points, and do not overlap, ask the maximum number of 1*2 can be covered by the rectangle, the output scheme, there is SPJ.

Input Description:

Multiple sets of data, first two n,m per group (if n and M are 0, end program)

and give the K

Then we give the coordinates of the waste point by K two-tuple (x, y).

Solving

The algorithm that follows the first two posts is out of order because the scheme is wrong.

So we're going to dye it in black and white.

Connect the four-connected directions only from (x, y) (X+y is odd), and then match the binary graph.

Where the match array value is the matching object.

Code

#include <cstring> #include <algorithm> #include <cstdlib> #include <cmath> #include <cstdio >using namespace Std;const int n=105,k=55;int dx[4]={0, 0,-1, 1};int dy[4]={-1, 1, 0, 0};int n,m,k,cnt,pl[n][n],tn[n][ N],bj[k],x[k],y[k];int g[k][k],vis[k],match[k];bool Check (int x,int y) {return 1<=x&&x<=n&&1 <=y&&y<=m&&tn[x][y];} BOOL Match (int x) {for (int i=1;i<=cnt;i++) if (!vis[i]&&g[x][i]) {vis[i]=1;if (!match[i]| | Match (Match[i])) {Match[i]=x;return 1;}} return 0;} int Hungary () {int res=0;memset (match,0,sizeof match), for (int i=1;i<=cnt;i++) {if (!bj[i]) Continue;memset (vis,0, sizeof Vis); if (Match (i)) res++;} return res;} int main () {while (~scanf ("%d%d", &n,&m) && (n| | m) {scanf ("%d", &k), memset (pl,0,sizeof PL); for (int i=1,x,y;i<=k;i++) scanf ("%d%d", &x,&y), pl[x][y]=1 ; memset (tn,0,sizeof tn); cnt=0;for (int i=1;i<=n;i++) for (int j=1;j<=m;j++) if (!pl[i][j]) {bj[tn[i][j]=++cnt]= (i +J) &1;x[Cnt]=i,y[cnt]=j;} memset (g,0,sizeof g); for (int. i=1;i<=n;i++) for (int. j=1;j<=m;j++) if ((i+j) &1) for (int d=0;d<4;d++) {int a=i +dx[d],b=j+dy[d];if (check (b)) g[tn[i][j]][tn[a][b]]=1;} int ans=hungary ();p rintf ("%d\n", ans), for (int i=1;i<=cnt;i++) if (Match[i]) printf ("(%d,%d)-(%d,%d) \ n", X[i],y[i] , X[match[i]],y[match[i]]);} return 0;}

　　

HDU1507 Uncle Tom's inherited land* binary map matching Hungarian algorithm black and white dyeing