[HDOJ2255]奔小康赚大钱（二分图最大匹配， KM算法）

题目链接：http://acm.split.hdu.edu.cn/showproblem.php?pid=2255

题意：很明显了，连图都是明摆着的。带权值的最大匹配，直接用km算法。

  1 /*
  2 ━━━━━┒ギリギリ♂ eye！
  3 ┓┏┓┏┓┃キリキリ♂ mind！
  4 ┛┗┛┗┛┃＼○／
  5 ┓┏┓┏┓┃ /
  6 ┛┗┛┗┛┃ノ)
  7 ┓┏┓┏┓┃
  8 ┛┗┛┗┛┃
  9 ┓┏┓┏┓┃
 10 ┛┗┛┗┛┃
 11 ┓┏┓┏┓┃
 12 ┛┗┛┗┛┃
 13 ┓┏┓┏┓┃
 14 ┃┃┃┃┃┃
 15 ┻┻┻┻┻┻
 16 */
 17 #include <algorithm>
 18 #include <iostream>
 19 #include <iomanip>
 20 #include <cstring>
 21 #include <climits>
 22 #include <complex>
 23 #include <fstream>
 24 #include <cassert>
 25 #include <cstdio>
 26 #include <bitset>
 27 #include <vector>
 28 #include <deque>
 29 #include <queue>
 30 #include <stack>
 31 #include <ctime>
 32 #include <set>
 33 #include <map>
 34 #include <cmath>
 35 using namespace std;
 36 #define fr first
 37 #define sc second
 38 #define cl clear
 39 #define BUG puts("here!!!")
 40 #define W(a) while(a--)
 41 #define pb(a) push_back(a)
 42 #define Rint(a) scanf("%d", &a)
 43 #define Rs(a) scanf("%s", a)
 44 #define Cin(a) cin >> a
 45 #define FRead() freopen("in", "r", stdin)
 46 #define FWrite() freopen("out", "w", stdout)
 47 #define Rep(i, len) for(int i = 0; i < (len); i++)
 48 #define For(i, a, len) for(int i = (a); i < (len); i++)
 49 #define Cls(a) memset((a), 0, sizeof(a))
 50 #define Clr(a, x) memset((a), (x), sizeof(a))
 51 #define Full(a) memset((a), 0x7f7f7f, sizeof(a))
 52 #define lrt rt << 1
 53 #define rrt rt << 1 | 1
 54 #define pi 3.14159265359
 55 #define RT return
 56 #define lowbit(x) x & (-x)
 57 #define onecnt(x) __builtin_popcount(x)
 58 typedef long long LL;
 59 typedef long double LD;
 60 typedef unsigned long long ULL;
 61 typedef pair<int, int> pii;
 62 typedef pair<string, int> psi;
 63 typedef pair<LL, LL> pll;
 64 typedef map<string, int> msi;
 65 typedef vector<int> vi;
 66 typedef vector<LL> vl;
 67 typedef vector<vl> vvl;
 68 typedef vector<bool> vb;
 69 
 70 const int maxn = 330;
 71 const int inf = 0x3f3f3f3f;
 72 int n;
 73 int nx,ny;
 74 int G[maxn][maxn], mp[maxn][maxn];
 75 int linker[maxn],lx[maxn],ly[maxn];
 76 int slack[maxn];
 77 bool visx[maxn],visy[maxn];
 78 
 79 bool dfs(int x) {
 80     visx[x] = true;
 81     for(int y = 0; y < ny; y++) {
 82         if(visy[y])continue;
 83         int tmp = lx[x] + ly[y] - G[x][y];
 84         if(tmp == 0) {
 85             visy[y] = true;
 86             if(linker[y] == -1 || dfs(linker[y])) {
 87                 linker[y] = x;
 88                 return true;
 89             }
 90         }
 91         else if(slack[y] > tmp)
 92             slack[y] = tmp;
 93     }
 94     return false;
 95 }
 96 int km() {
 97     memset(linker,-1,sizeof(linker));
 98     memset(ly,0,sizeof(ly));
 99     for(int i = 0;i < nx;i++) {
100         lx[i] = -inf;
101         for(int j = 0;j < ny;j++)
102             if(G[i][j] > lx[i])
103                 lx[i] = G[i][j];
104     }
105     for(int x = 0;x < nx;x++) {
106         for(int i = 0;i < ny;i++)
107             slack[i] = inf;
108         while(true) {
109             memset(visx,false,sizeof(visx));
110             memset(visy,false,sizeof(visy));
111             if(dfs(x))break;
112             int d = inf;
113             for(int i = 0;i < ny;i++)
114                 if(!visy[i] && d > slack[i])
115                     d = slack[i];
116             for(int i = 0;i < nx;i++)
117                 if(visx[i])
118                     lx[i] -= d;
119             for(int i = 0;i < ny;i++) {
120                 if(visy[i])ly[i] += d;
121                 else slack[i] -= d;
122             }
123         }
124     }
125     int res = 0;
126     for(int i = 0;i < ny;i++)
127         if(linker[i] != -1)
128             res += G[linker[i]][i];
129     return res;
130 }
131 
132 int main() {
133     // FRead();
134     while(~Rint(n)) {
135         nx = ny = n;
136         Rep(i, n) {
137             Rep(j, n) {
138                 Rint(G[i][j]);
139             }
140         }
141         printf("%d\n", km());
142     }
143     RT 0;
144 }

 

posted @ 2016-08-25 11:25  Kirai  阅读(144)  评论(0)  编辑  收藏  举报