Bzoj 4013 HNOI2015 Experiment comparing tree-shape dp+ Combinatorial mathematics

Topic: Given a picture, each edge has ' = ' and ' < ' two properties, each point in the degree of a maximum of 1, to find out how many of this graph can be pressed into the ' = ' and ' < ' connected sequence
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#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define M#define MOD 1000000007using namespace STD;structabcd{intTo,next;} TABLE[M];intHead[m],tot;intN,m;intC[M][M],F[M][M];intA[M][M],DEGREE[M];intV[m],t;voidADD (intXintY) {table[++tot].to=y;    TABLE[TOT].NEXT=HEAD[X]; Head[x]=tot;}namespaceunion_find_set{intFA[M];intFind (intx) {if(!fa[x]| | FA[X]==X)returnFa[x]=x;returnFa[x]=find (Fa[x]); }voidUnion (intXintY) {x=find (x); Y=find (y);if(x==y)return;    Fa[x]=y; }}voidPretreatment () {intI,j; for(i=0; i<=n;i++) {c[i][0]=1; for(j=1; j<=i;j++) c[i][j]= (c[i-1][j]+c[i-1][j-1])%mod; }}voidDFS (intx) {intI v[x]=t; for(I=head[x];i;i=table[i].next) {if(v[table[i].to]==t)Throw true;if(V[table[i].to])Continue;       DFS (table[i].to); }}voidTREE_DP (intx) {inti,j,k,l; f[x][0]=1; for(I=head[x];i;i=table[i].next) {TREE_DP (table[i].to);Static intG[M];memset(g,0,sizeofg); for(j=1; j<=n;j++) for(k=0; k<=j;k++) for(l=j-k;l<=j;l++) (G[j] + = (Long Long) f[x][k] * F[table[i].to][l]% mod * c[j][k]% mod * c[k][k+l-j]% mod)%=mod;memcpy(F[x],g,sizeofg); } for(i=n+1; i;i--) f[x][i]=f[x][i-1]; f[x][0]=0;}intMain () {using namespaceUnion_find_set;intI,j,x,y;Charp[Ten];Cin>>n>>m; Pretreatment (); for(i=1; i<=m;i++) {scanf("%d%s%d", &x,p,&y);if(p[0]==' = ') Union (x, y);ElseADD (x, y); } for(x=1; x<=n;x++) for(I=head[x];i;i=table[i].next) A[find (x)][find (table[i].to)]=1;memset(Head,0,sizeofHead); tot=0; for(i=1; i<=n;i++) for(j=1; j<=n;j++)if(A[i][j]) ADD (I,J), degree[j]++; for(i=1; i<=n;i++)if(Find (i) ==i&&!v[i]) {Try{++t;            DFS (i); }Catch(BOOL)            {cout<<0<<endl;return 0; }        } for(i=1; i<=n;i++)if(Find (i) ==i&&!degree[i]) ADD (0, i); TREE_DP (0);intans=0; for(i=1; i<=n+1; i++) (ans+=f[0][i])%=mod;cout<<ans<<endl;return 0;}

Bzoj 4013 HNOI2015 Experiment comparing tree-shape dp+ Combinatorial mathematics