[代码]UVALive 5882 Racing Car Trail

Abstract

UVALive 5882 Racing Car Trail

博弈 二分图

解题报告见http://www.cnblogs.com/jffifa/archive/2011/12/17/2291069.html

Body

代码写得又长又烂。

#include <cstdio>
#include <cstring>
#include <map>
#include <algorithm>
#include <vector>
using namespace std;

typedef pair<int, int> pr;
pr (*mkpr)(int, int)=make_pair;

const int S = 10005;
int di[] = {0, 1, 0, -1};
int dj[] = {1, 0, -1, 0};

int X, Y;
int N, M;
int ban;
vector<int> adj[S], radj[S];
int match[S];
int m[S], rm[S];
int matchcnt;
bool vis[S];
char mdk[105][105];
char ans[105][105];
int cnt;
int f[105][105];
map<int, pr> g;

bool dfs(vector<int> adj[], int u)
{
    int v;
    for (int i = 0; i < adj[u].size(); ++i)
    {
        v = adj[u][i];
        if (v==ban || vis[v]) continue;
        vis[v] = 1;
        if (!match[v] || dfs(adj, match[v]))
        {
            match[v] = u;
            return 1;
        }
    }
    return 0;
}

int hungarian()
{
    int res = 0;
    memset(match, 0, sizeof(match));
    for (int u = 1; u <= X; ++u)
    {
        memset(vis, 0, sizeof(vis));
        if (dfs(adj, u)) ++res;
    }
    return res;
}

int main()
{
    int i, j, k, u, v;
    while (scanf("%d%d", &N, &M), N||M)
    {
        ban = cnt = X = Y = 0;
        g.clear();
        for (i = 0; i < N; ++i)
            scanf("%s", mdk[i]);
        for (i = 0; i < N; ++i)
            for (j = 0; j < M; ++j)
            {
                if (mdk[i][j]=='X'||(i+j)&1) continue;
                X++;
                cnt++;
                f[i][j] = cnt;
                g[cnt] = mkpr(i, j);
            }
        for (i = 0; i < N; ++i)
            for (j = 0; j < M; ++j)
            {
                if (mdk[i][j]=='X'||((i+j)&1)==0) continue;
                Y++;
                cnt++;
                f[i][j] = cnt;
                g[cnt] = mkpr(i, j);
            }
        for (u = 1; u <= cnt; ++u)
        {
            adj[u].clear();
            radj[u].clear();
        }
        for (i = 0; i < N; ++i)
            for (j = 0; j < M; ++j)
            {
                if (mdk[i][j]=='X'||((i+j)&1)!=0) continue;
                for (k = 0; k < 4; ++k)
                {
                    int ni = i+di[k];
                    int nj = j+dj[k];
                    if (ni>=0&&ni<N&&nj>=0&&nj<M&&mdk[ni][nj]!='X')
                    {
                        adj[f[i][j]].push_back(f[ni][nj]);
                        radj[f[ni][nj]].push_back(f[i][j]);
                    }
                }
            }
        matchcnt = hungarian();
        memset(ans, 0, sizeof(ans));
        memset(m, 0, sizeof(m));
        memset(rm, 0, sizeof(rm));
        for (u = X+1; u <= cnt; ++u)
        {
            m[u] = match[u];
            if (!m[u])
            {
                i = g[u].first;
                j = g[u].second;
                ans[i][j] = 'B';
            }
            else rm[m[u]] = u;
        }
        for (u = 1; u <= X; ++u)
        {
            if (!rm[u])
            {
                i = g[u].first;
                j = g[u].second;
                ans[i][j] = 'B';
            }
        }
        for (i = 0; i < N; ++i)
            for (j = 0; j < M; ++j)
            {
                if (ans[i][j]) continue;
                if (mdk[i][j]=='X')
                {
                    ans[i][j] = 'X';
                    continue;
                }
                ban = f[i][j];
                memset(vis, 0, sizeof(vis));
                if ((i+j)&1)
                {
                    memcpy(match, m, cnt+1<<2);
                    u = match[f[i][j]];
                    match[f[i][j]] = 0;
                    if (dfs(adj, u)) ans[i][j] = 'B';
                    else ans[i][j] = 'A';
                }
                else
                {
                    memcpy(match, rm, cnt+1<<2);
                    u = match[f[i][j]];
                    match[f[i][j]] = 0;
                    if (dfs(radj, u)) ans[i][j] = 'B';
                    else ans[i][j] = 'A';
                }
            }
        for (i = 0; i < N; ++i)
            puts(ans[i]);
        puts("");
    }
    return 0;
}