POJ 2175 Evacuation Plan

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cmath>
  5 #include <algorithm>
  6 #include <climits>
  7 #include <vector>
  8 #include <queue>
  9 #include <cstdlib>
 10 #include <string>
 11 #include <set>
 12 #include <stack>
 13 #define LL long long
 14 #define pii pair<int,int>
 15 #define INF 0x3f3f3f3f
 16 using namespace std;
 17 const int maxn = 500;
 18 struct arc{
 19     int to,flow,cost,next;
 20     arc(int x = 0,int y = 0,int z = 0,int nxt = -1){
 21         to = x;
 22         flow = y;
 23         cost = z;
 24         next = nxt;
 25     }
 26 };
 27 arc e[maxn*maxn];
 28 int head[maxn],d[maxn],x[maxn],y[maxn],c[maxn];
 29 int tot,S,T,n,m,sf[maxn],bf[maxn],p[maxn],cnt[maxn];
 30 bool in[maxn];
 31 void add(int u,int v,int f1,int f2,int co){
 32     e[tot] = arc(v,f1,co,head[u]);
 33     head[u] = tot++;
 34     e[tot] = arc(u,f2,-co,head[v]);
 35     head[v] = tot++;
 36 }
 37 int getDis(int i,int j){
 38     return abs(x[i] - x[j]) + abs(y[i] - y[j]) + 1;
 39 }
 40 int spfa(){
 41     for(int i = S; i <= T; ++i){
 42         d[i] = INF;
 43         cnt[i] = 0;
 44         in[i] = false;
 45         p[i] = -1;
 46     }
 47     queue<int>q;
 48     d[T] = 0;
 49     q.push(T);
 50     while(!q.empty()){
 51         int u = q.front();
 52         q.pop();
 53         in[u] = false;
 54         for(int i = head[u]; ~i; i = e[i].next){
 55             if(e[i].flow && d[e[i].to] > d[u] + e[i].cost){
 56                 d[e[i].to] = d[u] + e[i].cost;
 57                 p[e[i].to] = i;
 58                 if(!in[e[i].to]){
 59                     in[e[i].to] = true;
 60                     if(++cnt[e[i].to] > T) return e[i].to;
 61                     q.push(e[i].to);
 62                 }
 63             }
 64         }
 65     }
 66     return -1;
 67 }
 68 int main(){
 69     while(~scanf("%d %d",&n,&m)){
 70         memset(head,-1,sizeof(head));
 71         memset(sf,0,sizeof(sf));
 72         memset(bf,0,sizeof(bf));
 73         T = n + m + 1;
 74         S = tot = 0;
 75         for(int i = 1; i <= n + m; ++i)
 76             scanf("%d %d %d",x+i,y+i,c+i);
 77         for(int i = 1; i <= n; ++i){
 78             for(int j = 1; j <= m; ++j){
 79                 int tmp = 0;
 80                 scanf("%d",&tmp);
 81                 add(i,j+n,INF - tmp,tmp,getDis(i,j+n));
 82                 sf[j] += tmp;
 83                 bf[i] += tmp;
 84             }
 85         }
 86         for(int i = 1; i <= n; ++i) add(S,i,c[i] - bf[i],bf[i],0);
 87         for(int i = 1; i <= m; ++i) add(i+n,T,c[i+n] - sf[i],sf[i],0);
 88         int u,v,o = spfa();
 89         if(o == -1) puts("OPTIMAL");
 90         else{
 91             memset(in,false,sizeof(in));
 92             while(!in[o]){
 93                 in[o] = true;
 94                 o = e[p[o]^1].to;
 95             }
 96             v = u = o;
 97             do{
 98                 u = e[p[v]^1].to;
 99                 e[p[v]].flow--;
100                 e[p[v]^1].flow++;
101                 v = u;
102 
103             }while(u != o);
104             puts("SUBOPTIMAL");
105             for(int i = 1; i <= n; ++i){
106                 for(int j = 1; j <= m; ++j){
107                     printf("%d%c",e[(i-1)*m*2 + 2*(j-1)+1].flow,j == m?‘\n‘:‘ ‘);
108                 }
109             }
110         }
111     }
112     return 0;
113 }