Assignment HDU

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Assignment

 HDU - 2853 

题意:题意直接那松神的题意了。给了你n个公司和m个任务,然后给你了每个公司处理每个任务的效率。然后他已经给你了每个公司的分配方案,让你求出最多能增大多少效率(即最大权值匹配减去原来的),然后问你至少要修改多少个关系(即修改多少条边)   

思路:关键在于最小修改的老边,很巧妙的将老边和新边的权值做了修改,使得并且不改变km里面的顺序,可以说是很巧妙的了。之后就就直接跑km的板子就好了,挺好的题目,难在新旧边的处理。

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<sstream>
#include<cmath>
#include<stack>
#include<map>
#include<cstdlib>
#include <vector>
#include<queue>
using namespace std;
const int INF = 0x3f3f3f3f;
const int maxn = 1e3+5;
int nx,ny,k;
int g[maxn][maxn];
int linker[maxn],lx[maxn],ly[maxn];
int slack[maxn];
bool visx[maxn],visy[maxn];
map<pair<int,int>,int>mp;
bool dfs(int x)
{
    visx[x] =  true;
    for(int y=1;y<=ny;y++)
    {
        if(visy[y])
            continue;
        int tmp = lx[x] + ly[y] -g[x][y];
        if(tmp == 0)
        {
            visy[y] = true;
            if(linker[y] == -1 || dfs(linker[y]))
            {
                linker[y]  = x;
                return true;
            }
        }
        else if(slack[y] > tmp)
            slack[y] = tmp;
    }
    return false;
}
int KM()
{
    memset(linker,-1,sizeof linker);
    memset(ly,0,sizeof ly);
    for(int i=1;i<=nx;i++)
    {
        lx[i] = -INF;
        for(int j=1;j<=ny;j++)
        {
            if(g[i][j] > lx[i])
                lx[i] = g[i][j];
        }
    }
    for(int x = 1;x <= nx ;x++)
    {
        for(int i=1;i<=ny;i++)
            slack[i] = INF;
        while(true)
        {
            memset(visx,false,sizeof visx);
            memset(visy,false,sizeof visy);
            if(dfs(x))
                break;
            int d = INF;
            for(int i = 1;i <= ny;i ++ )
                if(!visy[i] && d > slack[i])
                    d = slack[i];
            for(int i = 1;i <= nx; i++)
                if(visx[i])
                    lx[i] -= d;
            for(int i = 1; i <= ny; i++)
            {
                if(visy[i])
                    ly[i] += d;
                else
                    slack[i] -= d;
            }
        }
    }
    int res = 0;
    for(int i = 1; i <= ny; i++)
        if(linker[i] != -1)
            res += g[linker[i]][i];
    return res;
}
int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m))
    {
        mp.clear();
        memset(g,0,sizeof g);
        for(int i=1;i<=n;i++) {
            for (int j = 1; j <= m; j++) {
                int a;
                scanf("%d", &a);
                mp[make_pair(i, j)] = a;
                g[i][j] = a * (n + 1);
            }
        }
        int sum = 0;
        for(int i=1;i<=n;i++)
        {
            int b;
            scanf("%d",&b);
            g[i][b] += 1;
            sum += mp[make_pair(i,b)];
        }
        nx = n;
        ny = m;
        int ans = KM();
        printf("%d %d
",n-ans%(n+1),ans/(n+1)-sum);
    }

}
原文地址:https://www.cnblogs.com/smallhester/p/10316535.html