【UVALive】4043 Ants KM匹配

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传送门：【UVALive】4043 Ants

题目分析：裸的最小权匹配。将权值取反进行最大权匹配即可。

代码如下：

#include<cmath>#include <cstdio>#include <cstring>#include <algorithm>using namespace std ;  typedef long long LL ;  #define rep( i , a , b ) for ( int i = a ; i < b ; ++ i )#define For( i , a , b ) for ( int i = a ; i <= b ; ++ i )#define rev( i , a , b ) for ( int i = a ; i >= b ; -- i )#define travel( e , H , u ) for ( Edge* e = H[u] ; e ; e = e -> next )#define clr( a , x ) memset ( a , x , sizeof a )#define cpy( a , x ) memcpy ( a , x , sizeof a )  const int MAXN = 105 ;const double INF = 1e18 ;const double eps = 1e-8 ;struct Point {double x , y ;} p1[MAXN] , p2[MAXN] ;int visx[MAXN] , visy[MAXN] , Time ;int Lx[MAXN] , Ly[MAXN] ;double dx[MAXN] , dy[MAXN] ;double G[MAXN][MAXN] ;double slack[MAXN] ;int n ;int sgn ( double x ) {return ( x > eps ) - ( x < -eps ) ;}int find ( int u ) {visx[u] = Time ;rep ( v , 0 , n ) {if ( visy[v] == Time ) continue ;double tmp = dx[u] + dy[v] - G[u][v] ;if ( !sgn ( tmp ) ) {visy[v] = Time ;if ( Ly[v] == -1 || find ( Ly[v] ) ) {Lx[u] = v ;Ly[v] = u ;return 1 ;}} else if ( slack[v] > tmp ) slack[v] = tmp ;}return 0 ;}void KM () {rep ( i , 0 , n ) {Lx[i] = Ly[i] = -1 ;dx[i] = -INF ;dy[i] = 0 ;rep ( j , 0 , n ) if ( G[i][j] > dx[i] ) dx[i] = G[i][j] ;}rep ( i , 0 , n ) {rep ( j , 0 , n ) slack[j] = INF ;while ( 1 ) {++ Time ;if ( find ( i ) ) break ;double d = INF ;rep ( j , 0 , n ) if ( visy[j] != Time && d > slack[j] ) d = slack[j] ;rep ( j , 0 , n ) if ( visx[j] == Time ) dx[j] -= d ;rep ( j , 0 , n ) if ( visy[j] == Time ) dy[j] += d ;}}}double dist ( const Point& a , const Point& b ) {double x = a.x - b.x ;double y = a.y - b.y ;return sqrt ( x * x + y * y ) ;}void solve () {int res = 0 ;rep ( i , 0 , n ) scanf ( "%lf%lf" , &p1[i].x , &p1[i].y ) ;rep ( i , 0 , n ) scanf ( "%lf%lf" , &p2[i].x , &p2[i].y ) ;rep ( i , 0 , n ) rep ( j , 0 , n ) G[i][j] = - dist ( p1[i] , p2[j] ) ;KM () ;rep ( i , 0 , n ) printf ( "%d\n" , Lx[i] + 1 ) ;}int main () {int flag = 0 ;while ( ~scanf ( "%d" , &n ) ) {if ( flag ) puts ( "" ) ;flag = 1 ;solve () ;}return 0 ;}

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