@OceanEye4年前
11/24
10:17
时隔两年的todolist
这题题解很多就只放代码了
【黑白染色建图+二分+网络流】
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 |
#include <cstdio> #include <queue> #include <algorithm> #include <cstring> #include <cstdlib> #include <cmath> #define ll long long #define INF 1LL<<58 #define p(x) ('0'<=x&&x<='9') #define For(i,l,r) for(int i=l;i<=r;i++) char cc; int C; template <class T> void read( T &x ) { x=0; cc=getchar(); C=1; while(!p(cc)) { if(cc=='-') C=-1; cc=getchar(); } while(p(cc)) { x=x*10+cc-48; cc=getchar(); } x*=C; } #undef p using namespace std; #define E 20000 #define SIZ 2000 #define N 100 #define S 0 #define T 1990 #define NXT nxt[i] #define TO edge[i].to #define FROM edge[i].from #define FLOW edge[i].flow struct Tedge { int from,to; ll flow; Tedge():from(0),to(0),flow(0){} Tedge(int _,int __,ll ___):from(_),to(__),flow(___){} }edge[E]; int nxt[E],e_tot,fst[SIZ+50]; void add_e(int _,int __,ll ___) { edge[e_tot]=Tedge(_,__,___); nxt[e_tot]=fst[_]; fst[_]=e_tot++; edge[e_tot]=Tedge(__,_,0); nxt[e_tot]=fst[__]; fst[__]=e_tot++; } int n,m; const int _x[5]={0,0,1,-1},_y[5]={1,-1,0,0}; #define calc(i,j) ((i-1)*m+j) // def black odd // def white even ll sum_b,sum_w,mx,tot; ll a[N][N]; void init(ll key) { int pt; e_tot=0; tot=0; memset(fst,-1,sizeof(fst)); memset(nxt,0,sizeof(nxt)); For(i,1,n) For(j,1,m) { pt=calc(i,j); if(((i+j)&1)) { add_e(S,pt,key-a[i][j]); tot+=key-a[i][j]; For(k,0,3) { if(i+_x[k]<=0||i+_x[k]>n||j+_y[k]<=0||j+_y[k]>m) continue; add_e(pt,calc(i+_x[k],j+_y[k]),INF); } } else add_e(pt,T,key-a[i][j]); } } ll flow; int d[SIZ+50],cnt[SIZ+50],p[SIZ]; int bfs() { memset(d,0,sizeof(d)); memset(cnt,0,sizeof(cnt)); static int x,queue[65540],i; static unsigned short int he=0,ta=0; queue[++he]=T; d[T]=1; while(he!=ta) { x=queue[++ta]; cnt[d[x]]++; for(i=fst[x];~i;i=NXT) if(!d[TO]&&!edge[i].flow) { d[TO]=d[x]+1; queue[++he]=TO; } } // For(i,1,n*m+1) printf("%d ",d[i]); // puts(""); return d[S]; } ll Augment() { static int node,i; static ll c; node=T; c=INF; while(node!=S) { i=p[node]; c=min(c,FLOW); node=FROM; } node=T; while(node!=S) { i=p[node]; FLOW-=c; edge[i^1].flow+=c; node=FROM; } return c; } void ISAP() { static int node,cur[SIZ+50]; static bool flag; flow=0; memset(cur,0,sizeof(cur)); if(!bfs()) return; node=S; for(int i=0;i<=SIZ-1;++i) cur[i]=fst[i]; while(d[S]<n*m+3) { if(node==T) { flow+=Augment(); node=S; } flag=false; for(int i=cur[node];~i;i=NXT) if(d[TO]==d[node]-1&&FLOW) { p[TO]=i; cur[node]=i; node=TO; flag=true; break; } if(flag) continue; int M=SIZ+10; for(int i=fst[node];~i;i=NXT) if(FLOW) M=min(M,d[TO]+1); if(--cnt[d[node]]==0) return; cnt[d[node]=M]++; cur[node]=fst[node]; if(node!=S)node=edge[p[node]].from; } } ll solve1() { // puts("-----"); ll L=mx,R=8000000000LL,mid; while(L!=R) { mid=(L+R)>>1; init(mid); ISAP(); if(tot!=flow) L=mid+1; else R=mid; // printf("%lld %lld %lld\n",mid,flow,tot); } init(L); ISAP(); // puts("-----"); if(tot==flow) return flow; return -1; } void solve2(ll state) { if(state<mx) { printf("-1\n"); return; } init(state); ISAP(); printf("%lld\n",flow==tot?flow:-1); // printf("flow %lld\n",flow); return; } #undef E #undef FLOW #undef NXT #undef N #undef NXT #undef S #undef SIZ #undef T #undef TO #undef calc ll pre() { sum_b=sum_w=mx=0; read(n); read(m); For(i,1,n) For(j,1,m) { read(a[i][j]); mx=max(a[i][j],mx); ((i+j)&1)?(sum_w+=a[i][j]):(sum_b+=a[i][j]); } // -1 fail 0 b=w // -1 fail 1 b=w+1 if(!(n&m&1)) return sum_b==sum_w?-2:-1; // printf("sb-sw%lld\n",sum_b-sum_w); return (0LL+sum_b-sum_w>=0)?(0LL+sum_b-sum_w):-1; } void Main() { static ll state; state=pre(); if(state==-1) { puts("-1"); return; } if(state==-2) printf("%lld\n",solve1()); else solve2(state); } int main() { #ifdef LOCAL freopen("BZOJ2756.in","r",stdin); #endif int T; for(read(T);T;--T) Main(); return 0; } |