用到了KM算法 ,发现自己没有这个模板,搜索学习一下上海大学final大神,http://www.cnblogs.com/kuangbin/p/3228861.html
1 #include <stdio.h> 2 #include <algorithm> 3 #include <string.h> 4 #include <iostream> 5 using namespace std; 6 7 /* KM算法 8 * 复杂度O(nx*nx*ny) 9 * 求最大权匹配 10 * 若求最小权匹配，可将权值取相反数，结果取相反数 11 * 点的编号从0开始 12 */ 13 const int N = 310; 14 const int INF = 0x3f3f3f3f; 15 int nx,ny;//两边的点数 16 int g[N][N];//二分图描述 17 int linker[N],lx[N],ly[N];//y中各点匹配状态，x,y中的点标号 18 int slack[N]; 19 bool visx[N],visy[N]; 20 21 bool DFS(int x) 22 { 23 visx[x] = true; 24 for(int y = 0; y < ny; y++) 25 { 26 if(visy[y])continue; 27 int tmp = lx[x] + ly[y] - g[x][y]; 28 if(tmp == 0) 29 { 30 visy[y] = true; 31 if(linker[y] == -1 || DFS(linker[y])) 32 { 33 linker[y] = x; 34 return true; 35 } 36 } 37 else if(slack[y] > tmp) 38 slack[y] = tmp; 39 } 40 return false; 41 } 42 int KM() 43 { 44 memset(linker,-1,sizeof(linker)); 45 memset(ly,0,sizeof(ly)); 46 for(int i = 0;i < nx;i++) 47 { 48 lx[i] = -INF; 49 for(int j = 0;j < ny;j++) 50 if(g[i][j] > lx[i]) 51 lx[i] = g[i][j]; 52 } 53 for(int x = 0;x < nx;x++) 54 { 55 for(int i = 0;i < ny;i++) 56 slack[i] = INF; 57 while(true) 58 { 59 memset(visx,false,sizeof(visx)); 60 memset(visy,false,sizeof(visy)); 61 if(DFS(x))break; 62 int d = INF; 63 for(int i = 0;i < ny;i++) 64 if(!visy[i] && d > slack[i]) 65 d = slack[i]; 66 for(int i = 0;i < nx;i++) 67 if(visx[i]) 68 lx[i] -= d; 69 for(int i = 0;i < ny;i++) 70 { 71 if(visy[i])ly[i] += d; 72 else slack[i] -= d; 73 } 74 } 75 } 76 int res = 0; 77 for(int i = 0;i < ny;i++) 78 if(linker[i] != -1) 79 res += g[linker[i]][i]; 80 return res; 81 } 82 //HDU 2255 83 int main() 84 { 85 int n; 86 while(scanf("%d",&n) == 1) 87 { 88 for(int i = 0;i < n;i++) 89 for(int j = 0;j < n;j++) 90 scanf("%d",&g[i][j]); 91 nx = ny = n; 92 printf("%d ",KM()); 93 } 94 return 0; 95 }
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