[HDOJ3523]Image copy detection

二分图最小权值匹配KM算法~

#include <stdio.h>
  2 #include <string.h>
  3 #include <stdlib.h>
  4 #include <math.h>
  5 #include <assert.h>
  6 #include <ctype.h>
  7 #include <map>
  8 #include <string>
  9 #include <set>
 10 #include <bitset>
 11 #include <utility>
 12 #include <algorithm>
 13 #include <vector>
 14 #include <stack>
 15 #include <queue>
 16 #include <iostream>
 17 #include <fstream>
 18 #include <list>
 19 
 20 usingnamespace  std;
 21 
 22 constint MAXN =128;
 23 constint INF =1000000000;
 24 
 25 int  N;
 26 int  g[MAXN][MAXN];
 27 int  pre[MAXN];
 28 int  lx[MAXN], ly[MAXN], slack[MAXN];
 29 bool  visx[MAXN], visy[MAXN];
 30 
 31 int data[MAXN][MAXN];
 32 
 33 void  BuildGraph()
 34 {
 35 int  i, j, k, nr, nc;
 36 
 37     scanf("%d %d",&nc,&nr);
 38 for (i =0;i < nr;i++)
 39 for (j =0;j < nc;j++)
 40             scanf("%d",&data[i][j]);
 41 
 42     N = nc;
 43 
 44 for (i =0; i < N; i++)
 45 for (j =0; j < N; j++)
 46         {
 47 int sum =0;
 48 for (k =0;k < nr;k++)
 49                 sum += abs(i+1-data[k][j]);
 50             g[i][j] =-sum;
 51         }
 52 }
 53 
 54 bool  dfs(int  t)
 55 {
 56 int i;
 57     visx[t] =true;
 58 for (i =0; i < N; i++)
 59     {
 60 if (visy[i]) continue;
 61 int  tmp = lx[t]+ly[i]-g[t][i];
 62 if (tmp ==0)
 63         {
 64             visy[i] =true;
 65 if (pre[i] ==-1|| dfs(pre[i]))
 66             {
 67                 pre[i] = t;
 68 returntrue;
 69             }
 70         }
 71 elseif (slack[i] > tmp)
 72         {
 73             slack[i] = tmp;
 74         }
 75     }
 76 returnfalse;
 77 }
 78 int  KM()
 79 {
 80 int  i, j;
 81     memset(pre, -1, sizeof(pre));
 82     memset(ly, 0, sizeof(ly));
 83 for(i =0; i < N; i++)
 84         lx[i] =-INF;
 85 for(i =0; i < N; i++)
 86     {
 87 for(j =0; j < N; j++)
 88         {
 89 if(lx[i] < g[i][j])
 90                 lx[i] = g[i][j];
 91         }
 92     }
 93 for(i =0; i < N; i++)
 94     {
 95 for(j =0; j < N; j++)
 96             slack[j] = INF;
 97 while(1)
 98         {
 99             memset(visx, false, sizeof(visx));
100             memset(visy, false, sizeof(visy));
101 if(dfs(i)) break;
102 int  d = INF;
103 for(j =0; j < N; j++)
104 if(!visy[j] && slack[j] < d)
105                     d = slack[j];
106 for(j =0; j < N; j++)
107 if(visx[j]) lx[j] -= d;
108 for(j =0; j < N; j++)
109             {
110 if(visy[j]) ly[j] += d;
111 else  slack[j] -= d;
112             }
113         }
114     }
115 int  ans =0;
116 for(i =0; i < N; i++)
117     {
118 if(pre[i] !=-1)
119             ans -= g[pre[i]][i];
120     }
121 return  ans;
122 }
123 
124 
125 int  main()
126 {
127 int  T;
128     scanf("%d", &T);
129 for(int cc =1;cc <= T;cc++)
130     {
131         BuildGraph();
132 int  ans = KM();
133         printf("Case #%d: %d\n", cc, ans);
134     }
135 return0;
136 }