bzoj:1443: [JSOI2009] Game games

Original title Link: http://www.lydsy.com/JudgeOnline/problem.php?id=1443

Anyway, I can't think of a series ...

First the checkerboard black and white dyeing, that is, the same diagonal color, so that a lattice up and down are different colors.

Then we will find that the whole lattice color of a person's walk is the same.

The black and white lattice as a point extracted, placed on both sides, it becomes a two-minute chart, the whole process of the game becomes like the augmentation of Hungarian algorithm.

This suggests that we may be related to binary graph matching.

If a point must be in the maximum match, and the first piece is placed here small yy as long as along the matching side walk small AA on GG.

Note that this is necessarily in the maximum match, so do not worry about the occurrence of a non-matching point after the small yy no way to go, at this time can be pseudo-augmented to maintain the maximum number of matches unchanged and the starting point is not in the matching point.

For Hungarian algorithms, it is possible to find all points that are not necessarily in the maximum match through similar pseudo-augmentation.

For network streams, the points that are not cut off adjacent sides of the Yuanhui are definitely the answer, and for other points that can be answered, you can reach the meeting point or from the source point by taking the opposite edge (a similar interleaved path to Hungary). That is, in the residual network, the source point can be reached and in the binary map near the point of the source point, can reach the meeting point and in the binary map near the side of the meeting point (no two restrictions on GG) are the answer point. (Note that a one-way edge is built, that is, the initial flow of the opposite edge is 0)

#include <cstdio>#include<algorithm>#defineMN 110001using namespacestd;intRead_p,read_ca;inlineintRead () {read_p=0; read_ca=GetChar ();  while(read_ca<'0'|| Read_ca>'9') read_ca=GetChar ();  while(read_ca>='0'&&read_ca<='9') read_p=read_p*Ten+read_ca- -, read_ca=GetChar (); returnread_p;}Const intfx[4]={1,-1,0,0},fy[4]={0,0,1,-1};structna{intY,f,ne;} B[MN];intn,m,l[mn],be[101][101],nm=0, s,t,num=1, d[mn],g[mn],c[mn],mmh=0;BOOLBO[MN],O_O[MN];Chars[101][101];inlinevoidAddintXintYintf) {b[++num].y=y;b[num].f=f;b[num].ne=l[x];l[x]=num;} Inlinevoid inch(intXintYintf) {Add (x,y,f); Add (Y,x,0);}intSapintXintf) {    if(x==t)returnF; intH=0, q;  for(intI=d[x];i;i=b[i].ne)if(b[i].f&&g[x]==g[b[i].y]+1) {Q=sap (B[i].y,min (fh,b[i].f)); B[I].F-=q;b[i^1].f+=q;h+=q;d[x]=L[x]; if(h==f)returnh; if(G[S]==NM)returnh; }    if(!--C[g[x]] g[s]=nm;++c[++g[x];d [x]=L[x]; returnh;}voidDfsintXBOOLB) {    if(Bo[x])return; BO[X]=1; o_o[x]^=C;  for(intI=l[x];i;i=b[i].ne)if(b[i].f==B) DFS (B[I].Y,B);}intMain () {registerinti,j,k; N=read (); m=read ();  for(i=1; i<=n;i++) scanf ("%s", s[i]+1);  for(i=1; i<=n;i++)     for(j=1; j<=m;j++)if(s[i][j]=='.') be[i][j]=++nm; S=++NM; t=++nm;  for(i=1; i<=n;i++)     for(j=1; j<=m;j++)    if(s[i][j]=='.')     for(k=0;k<4; k++)    if(s[i+fx[k]][j+fy[k]]=='.')    if((I+J) &1)inch(Be[i+fx[k]][j+fy[k]],be[i][j],1);Else inch(Be[i][j],be[i+fx[k]][j+fy[k]),1);  for(i=1; i<=n;i++)     for(j=1; j<=m;j++)    if(s[i][j]=='.')if(Mmh++,o_o[be[i][j]]= (I+J) &1))inch(Be[i][j],t,1);Else inch(S,be[i][j],1);  for(; g[s]<nm;mmh-=2*SAP (S,1E9)); if(!MMH)returnPuts"lose"),0; Puts ("WIN"); DFS (S,1);d FS (T,0);  for(i=1; i<=n;i++)     for(j=1; j<=m;j++)    if(s[i][j]=='.'&AMP;&AMP;BO[BE[I][J]]&AMP;&AMP;O_O[BE[I][J]]) printf ("%d%d\n", i,j);}

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bzoj:1443: [JSOI2009] Game games