sgu243：Broken Chessboard(搜索+优化)

来源：互联网发布：东阿县南湖行知学校编辑：程序博客网时间：2024/06/07 16:28

题目大意：
给你一个20∗20的桌面，上面有一些用不同字母标号的联通块，联通块可以旋转90,180,270度，(为 . 则表示是桌子)。已知这些联通块是由一个N∗N,(N<=5)的网格拆开得到的，要你求出一种拼接方案拼出N∗N的网格。

分析：
搞了一下午，真是*了狗了…
把所有的连通块及其旋转后的块存下来，按照大小排个序，去掉重复的(我不会告诉你我不去掉也可以过…)，然后挨个放进去就行了。

AC code：

#include <cstdio>#include <cmath>#include <cstdlib>#include <cstring>#include <cctype>#include <algorithm>#include <string>#include <sstream>#include <iostream>#include <map>#include <set>#include <list>#include <stack>#include <queue>#include <vector>#define pb push_back#define mp make_pair#define ONLINE_JUDGEtypedef long long LL;typedef double DB;typedef long double LD;using namespace std;const int MAXN = 7;const int MAXL = 22;const int INF = 0x3f3f3f3f;int n;char g[MAXL][MAXL];bool vis[MAXL][MAXL];struct piece {    int w, h, s, c;    char g[MAXN][MAXN];    piece()    {        w = h = s = c = 0;        memset(g, 0, sizeof(g));        }    friend bool operator == (const piece &a, const piece &b)    {        if(a.w != b.w || a.h != b.h) return false;        for(int i = 1; i <= a.h; ++i)            for(int j = 1; j <= a.w; ++j)                if(a.g[i][j] != b.g[i][j])                    return false;        return true;        }}a[MAXN*MAXN], b[MAXN*MAXN*4];int sum[MAXN*MAXN];int k;struct pot{    int x, y;    pot(int x = 0, int y = 0):x(x),y(y){}}node[MAXN*MAXN];int tot;int dx[4] = {0,0,1,-1};int dy[4] = {1,-1,0,0};#define inside(x, y) ((x)>=1 && (x)<=20 && (y) >= 1 && (y) <= 20)void dfs(int x, int y){    vis[x][y] = true;    node[++tot] = pot(x, y);    a[k].s++, a[k].c = g[x][y]-'A'+1;    for(register int i = 0; i < 4; ++i)    {        int tx = x+dx[i], ty = y+dy[i];        if(inside(tx, ty) && !vis[tx][ty] && g[tx][ty] == g[x][y])            dfs(tx, ty);    }}inline piece rotate(const piece &a){    piece ret;    ret.w = a.h, ret.h = a.w;    ret.s = a.s, ret.c = a.c;    for(register int i = 1; i <= a.h; ++i)        for(register int j = 1; j <= a.w; ++j)            ret.g[j][ret.w-i+1] = a.g[i][j];    return ret;}void make_piece(){    int lm = INF, rm = -INF;    int dm = INF, um = -INF;    for(register int i = 1; i <= tot; ++i)    {        if(node[i].y < lm) lm = node[i].y;        if(node[i].y > rm) rm = node[i].y;        if(node[i].x < dm) dm = node[i].x;        if(node[i].x > um) um = node[i].x;    }    a[k].w = rm-lm+1, a[k].h = um-dm+1;    for(register int i = 1; i <= tot; ++i)        a[k].g[node[i].x-dm+1][node[i].y-lm+1] = g[node[i].x][node[i].y];}char graph[MAXN][MAXN];inline bool check(int x, int y, int p){    for(register int i = x; i <= x+b[p].h-1; ++i)        for(register int j = y; j <= y+b[p].w-1; ++j)            if(b[p].g[i-x+1][j-y+1] && graph[i][j])                return false;    return true;    }inline void cover(int x, int y, int p){    for(register int i = x; i <= x+b[p].h-1; ++i)        for(register int j = y; j <= y+b[p].w-1; ++j)            if(b[p].g[i-x+1][j-y+1]) graph[i][j] = b[p].g[i-x+1][j-y+1];}inline void recover(int x, int y, int p){    for(register int i = x; i <= x+b[p].h-1; ++i)        for(register int j = y; j <= y+b[p].w-1; ++j)            if(b[p].g[i-x+1][j-y+1]) graph[i][j] = 0;}void solve(int now){    if(now == k+1)    {        for(int i = 1; i <= n; ++i)            puts(graph[i]+1);        exit(0);        }    for(register int p = sum[now-1]+1; p <= sum[now]; ++p)        for(register int i = 0; i+b[p].h <= n; ++i)            for(register int j = 0; j+b[p].w <= n; ++j)                if(check(i+1, j+1, p))                {                    cover(i+1, j+1, p);                    solve(now+1);                    recover(i+1, j+1, p);                   }}inline bool cmp(const piece &a, const piece &b){    return a.s > b.s || (a.s == b.s && a.c < b.c);  }int main(){    #ifndef ONLINE_JUDGE    freopen("input.txt", "r", stdin);    freopen("output.txt", "w", stdout);    #endif    scanf("%d", &n);    for(register int i = 1; i <= 20; ++i)        scanf("%s", g[i]+1);    for(register int i = 1; i <= 20; ++i)        for(register int j = 1; j <= 20; ++j)            if(g[i][j] != '.' && !vis[i][j])            {                k++;                tot = 0;                dfs(i, j);                make_piece();            }    for(register int i = 1; i <= k; ++i)        for(register int j = 0; j < 4; ++j)        {            b[++tot] = a[i];            a[i] = rotate(a[i]);        }    sort(b+1, b+tot+1, cmp);    tot = unique(b+1, b+tot+1)-b;    int tmp = 0;    for(int i = 1; i <= tot; ++i)        if(b[i].c != b[i+1].c)            sum[++tmp] = i;    solve(1);    #ifndef ONLINE_JUDGE    fclose(stdin);    fclose(stdout);    #endif    return 0;}

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