[SCOI2012]奇怪的游戏 (网络流)

  1 #include<queue>
  2 #include<cstdio> 
  3 #include<cstring>
  4 #include<iostream>
  5 #define MAXN 1010
  6 #define LL long long
  7 
  8 using namespace std;
  9 
 10 const LL INF=(1LL<<50);
 11 
 12 struct Quix {
 13     int to;
 14     int next;
 15     LL val;
 16 };
 17 Quix e[20010];
 18 
 19 int head[MAXN<<1],cur[MAXN<<1],tot=1;
 20 
 21 int T,n,m,src,decc,n1,n2,mx=-1;
 22 
 23 LL s1,s2;  //血的教训 忘了long long 
 24 
 25 int depth[MAXN<<1],a[50][50],color[50][50];
 26 
 27 int X[4]={0,1,-1,0};
 28 int Y[4]={1,0,0,-1};  //上下左右我竟然少搜了一个方向 
 29 
 30 queue<int> Q;
 31 
 32 inline void read(int&x) {
 33     int f=1;x=0;char c=getchar();
 34     while(c>‘9‘||c<‘0‘) {if(c==‘-‘) f=-1;c=getchar();}
 35     while(c>=‘0‘&&c<=‘9‘) {x=(x<<1)+(x<<3)+c-48;c=getchar();}
 36     x=x*f;
 37 }
 38 
 39 inline void add(int x,int y,LL z) {
 40     e[++tot].to=y;
 41     e[tot].val=z;
 42     e[tot].next=head[x];
 43     head[x]=tot;
 44 }
 45 
 46 inline void add_edge(int x,int y,LL z) {
 47     add(x,y,z);
 48     add(y,x,0);
 49 }
 50 
 51 inline int cal(int i,int j) {
 52     return (i-1)*m+j;
 53 }
 54 
 55 bool bfs() {
 56     for(int i=0;i<=decc;i++) cur[i]=head[i],depth[i]=-1;
 57     while(!Q.empty()) Q.pop();
 58     Q.push(src);
 59     depth[src]=0;
 60     while(!Q.empty()) {
 61         int u=Q.front();
 62         Q.pop();
 63         for(int i=head[u];i!=-1;i=e[i].next) {
 64             int to=e[i].to;
 65             if(e[i].val&&depth[to]==-1) {
 66                 Q.push(to);
 67                 depth[to]=depth[u]+1;
 68                 if(to==decc) return true;
 69             }
 70         }
 71     }
 72     return false;
 73 }
 74 
 75 LL dfs(int now,LL flow) {
 76     if(now==decc) return flow;
 77     LL used=0,delat;
 78     for(int & i=cur[now];i!=-1;i=e[i].next) {
 79         int to=e[i].to;
 80         if(e[i].val&&depth[to]==depth[now]+1) {
 81             delat=flow-used;
 82             delat=dfs(to,min(e[i].val,delat));
 83             e[i].val-=delat;
 84             e[i^1].val+=delat;
 85             used+=delat;
 86             if(used==flow) break;
 87         }
 88     }
 89     if(!used) depth[now]=-1;
 90     return used;
 91 }
 92 
 93 inline LL dinic() {
 94     LL ans=0;
 95     while(bfs()) 
 96       ans+=dfs(src,INF);
 97     return ans;
 98 }
 99 
100 inline bool check(LL x) {
101     LL cnt=0;
102     tot=1;
103     memset(head,-1,sizeof head);
104     for(int i=1;i<=n;i++)
105       for(int j=1;j<=m;j++)
106         if(color[i][j]) {
107             add_edge(src,cal(i,j),x-a[i][j]);
108             cnt+=x-a[i][j];
109             for(int k=0;k<4;k++) {
110                 int nx=i+X[k];
111                 int ny=j+Y[k];
112                 if(nx<1||nx>n||ny<1||ny>m) continue;
113                 add_edge(cal(i,j),cal(nx,ny),INF);
114             }
115         }
116         else add_edge(cal(i,j),decc,x-a[i][j]);
117     if(dinic()==cnt) return true;
118     return false;
119 }
120 
121 inline int hhh() {
122     read(T);
123     while(T--) {
124         mx=-1;
125         n1=n2=s1=s2=0;
126         read(n);read(m);
127         src=0;decc=n*m+1;
128         for(int i=1;i<=n;i++)
129           for(int j=1;j<=m;j++) {
130               read(a[i][j]);
131               color[i][j]=(i+j)&1;
132               mx=max(mx,a[i][j]);
133             if(color[i][j]) s1+=(LL)a[i][j],n1++;
134               else s2+=(LL)a[i][j],n2++;
135           }
136         if(n1!=n2) {
137             LL x=(s2-s1)/(n2-n1);
138             if(x>=mx) 
139               if(check(x)) {
140                   printf("%lld\n",(LL)x*n1-s1);
141                   continue;
142               }
143             printf("-1\n");
144         }
145         else {
146             if(s1!=s2) {
147                 printf("-1\n");
148                 continue;
149             }
150             LL l=mx,r=INF;
151             while(l<=r) {
152                 LL mid=(l+r)>>1;
153                 if(check(mid)) r=mid-1;
154                 else l=mid+1;
155             }
156             printf("%lld\n",(LL)l*n1-s1);
157         }
158     }    
159     return 0;
160 }
161 
162 int sb=hhh();
163 int main() {;}