Hdu 4594 difference (singular circle judgment + differential constraint)

Title Address: http://acm.hdu.edu.cn/showproblem.php?pid=4598

Train of thought: by test instructions know two points of the AI symbol is opposite, so if there is a singular circle, there must be no solution. Staining, Colour[i]==1 expressed as positive, colour[i]==2 expressed as negative. Since (b) the condition is sufficient and necessary, for the point in the diagram | A[I]-A[J] | >= T, for non-image midpoint | A[I]-A[J] | < T, i.e. | A[I]-A[J] | <= T-1. So the midpoint of the figure, if COLOUR[I]==1,A[I]-A[J] >= T, otherwise a[j]-a[i] >= T. In the case of a non-graph midpoint, if there is a negative ring in the graph, there is no solution.

#include <cstdio> #include <queue> #include <vector> #include <cstring> #include <iostream    > #include <algorithm> #define debuusing namespace std;const int t=1111;const int maxn=350;struct node{int v,w; Node (int v=0,int w=0): V (v), W (w) {}};int n;queue<int> q;vector<int> g[maxn];char st[maxn][maxn];int Map[max n][maxn];vector<node> g[maxn];int dist[maxn],v[maxn];int colour[maxn],tot[maxn];void Find (int x,int flag) {//    cout<<x<< "" <<flag<<endl;    Colour[x]=flag; for (int i=0; i<g[x].size (); i++) if (!colour[g[x][i]]) Find (G[x][i],3-flag);}    int check () {//cout<< "Flag" <<endl;    memset (colour,0,sizeof (colour));    for (int i=1; i<=n; i++) if (!colour[i]) Find (i,1);    cout<< "Flag" <<endl;    for (int i=1, i<=n; i++) for (int j=0; j<g[i].size (); j + +) if (Colour[i]==colour[g[i][j]]) return 0; return 1;} void make () {for (int i=0; i<=n; i++) g[i].cLear (); for (int i=1, i<=n; i++) for (int j=i+1; j<=n; J + +) {//cout<<st[i-1][j-1]<< "" &l            t;<colour[i]<<endl; if (st[i-1][j-1]== ' 1 ') {if (colour[i]==1) {//cout<<i<                    < "<<j<<" <<-T<<endl;                G[i].push_back (Node (j,-t)); } else {//cout<<j<< "" <<i<< "" <<-T<<                    Endl                G[j].push_back (Node (i,-t)); }} else {if (colour[i]==1) {//cout<                    <j<< "<<i<<" <<T-1<<endl;                G[j].push_back (Node (i,t-1)); } else {//cout<<i<< "" <<j<< "" <<t-1<&lt                    ; Endl; G[i].pusH_back (Node (j,t-1));        }}}/*for (int i=1; i<=n; i++) cout<<i<< "" <<colour[i]<<endl;            for (int i=1; i<=n; i++) {cout<<g[i].size () <<endl; for (int j=0; j<g[i].size (); j + +) cout<<i<< "" <<G[i][j].v<< "" &LT;&LT;G[I][J].W&L        t;<endl;    }*/}int solve () {make ();    cout<< "Flag" <<endl;    while (!q.empty ()) Q.pop ();    memset (tot,0,sizeof (tot));    memset (dist,0,sizeof (Dist));        for (int i=1; i<=n; i++) {v[i]=1;    Q.push (i);        } while (!q.empty ()) {int Now=q.front ();        cout<<now<<endl;        Q.pop (), v[now]=0;            for (int i=0; i<g[now].size (); i++) {int nt=g[now][i].v;                if (DIST[NT]&GT;DIST[NOW]+G[NOW][I].W) {DIST[NT]=DIST[NOW]+G[NOW][I].W;                if (!v[nt]); {v[nt]=1;                    Q.push (NT);                if (++tot[nt]>n) return 0; }}}} return 1;}    int main () {#ifdef debug Freopen ("In.in", "R", stdin); #endif//debug int t;    scanf ("%d", &t);        while (t--) {scanf ("%d", &n);        GetChar ();        memset (map,0,sizeof (MAP));        for (int i=0; i<=n; i++) g[i].clear ();            for (int i=0; i<n; i++) {scanf ("%s", St[i]);            cout<<st[i]<<endl;        for (int j=0; j<n; J + +) if (st[i][j]== ' 1 ') g[i+1].push_back (j+1);        } if (check () &&solve ()) printf ("yes\n");    else printf ("no\n"); } return 0;}

Hdu 4594 difference (singular circle judgment + differential constraint)