[面试备] 暴搜 or 二分图的经典升级 ： hdu 1045 Fire Net 示例 [ 二分图 ]

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <vector>
#include <stack>
#include <deque>
#include <queue>
#include <bitset>
#include <list>
#include <map>
#include <set>
#include <iterator>
#include <algorithm>
#include <functional>
#include <utility>
#include <sstream>
#include <climits>
#include <cassert>
#define BUG puts("here!!!");

using namespace std;
const int N = 5;
const int M = 30;
char str

;
int p

;
int rp

;
int mmap[M][M];
int pre[M];
bool vis[M];
int n;
int x_id, y_id;
bool dfs(int u) {
for(int i = 1; i <= y_id; i++) {
if(mmap[u][i] && !vis[i]) {
vis[i] = true;
if(pre[i] == 0 || dfs(pre[i])) {
pre[i] = u;
return true;
}
}
}
return false;
}
int maxMatch() {
memset(pre, 0, sizeof(pre));
int num = 0;
for(int i = 1; i <= x_id; i++) {
memset(vis, 0, sizeof(vis));
if(dfs(i)) num++;
}
return num;
}
int main() {
while(cin >> n, n) {
for(int i = 0; i < n; i++) {
scanf("%s", str[i]);
}
memset(p, 0, sizeof(p));
memset(rp, 0, sizeof(rp));
x_id = 0, y_id = 0;
for(int i = 0; i < n; i++) {
int k = 0;
while(k < n) {
if(str[i][k] == '.') {
++x_id;
while(k < n && str[i][k] != 'X') {
p[i][k] = x_id;
k++;
}
}
else k++;
}
}
for(int i = 0; i < n; i++) {
int k = 0;
while(k < n) {
if(str[k][i] == '.') {
++y_id;
while(k < n && str[k][i] != 'X') {
rp[k][i] = y_id;
k++;
}
}
else k++;
}
}
memset(mmap, 0, sizeof(mmap));
for(int i = 0; i < n; i++) {
for(int j = 0; j < n; j++) {
if(str[i][j] == '.') {
mmap[p[i][j]][rp[i][j]] = 1;
}
}
}
printf("%d\n", maxMatch());
}
return 0;
}