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P2055.cpp
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118 lines (112 loc) · 3.67 KB
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#include <cstdio>
#include <cstdlib>
#include <vector>
#include <queue>
using namespace std;
typedef unsigned char byte; //n <= 50，一个字节足够
typedef byte vertex; //顶点，左图表示在学校住的人，右图表示床位
#define BYTE_MAX 0xff
#define NOT_A_VERTEX BYTE_MAX //表示不存在的顶点
struct Person {
bool is_student; //true则为在校生
bool go_home; //true则要回家，对于非在校生此项无效
vector<vertex> list; //可以睡的床位
~Person() {
vector<vertex>().swap(list);
}
};
queue<vertex> q; //顶点队列
bool hungarian(Person * p, int n) {
vertex * left_matching = new vertex[n]; //left_matching[v]表示左边顶点v匹配到的右边顶点
fill(left_matching, left_matching + n, NOT_A_VERTEX);
vertex * pre = new vertex[n]; //pre[v]表示若v找到新的匹配，则v原来的匹配可以给pre[v]
fill(pre, pre + n, NOT_A_VERTEX);
vertex * right_matching = new vertex[n]; //right_matching[v]表示右边顶点v匹配到的左边顶点
fill(right_matching, right_matching + n, NOT_A_VERTEX);
bool * visited = new bool[n]; //visited[v]表示BFS中右边顶点v是否访问过
bool result = true; //结果，初始化为true
for (vertex v = 0; v < n; v++) { //遍历所有人
if (p[v].is_student && p[v].go_home) continue; //若v是在校生且回家，则他不用匹配床位
//否则v需要匹配一个床位，v是左边顶点
fill(visited, visited + n, false);
q.push(v);
vertex front_v, adj_v, from, to, tmp_v;
while (!q.empty()) {
front_v = q.front();
q.pop();
for (auto it = p[front_v].list.begin(); it != p[front_v].list.end(); it++) {
adj_v = *it; //front_v的邻接点，(右边顶点)
if (!visited[adj_v]) {
visited[adj_v] = true;
if (right_matching[adj_v] != NOT_A_VERTEX) { //adj_v有匹配的左边顶点，即这张床有人匹配
q.push(right_matching[adj_v]); //这张床匹配的人进队列，相当于DFS中的递归
pre[right_matching[adj_v]] = front_v; //若以后这张床匹配的人找到了新的床匹配，那么原来这张床可以给front_v匹配，pre数组起到了记录的作用
}
else { //adj_v没有匹配的左边顶点，即这张床还没有人匹配，即front_v找到床位了
from = front_v;
to = adj_v;
while (from != NOT_A_VERTEX) {
tmp_v = left_matching[from]; //tmp_v为from原来的匹配，若from原来没有匹配，则tmp_v为NOT_A_VERTEX
left_matching[from] = to; //左边顶点from匹配到的右边顶点更新为to
right_matching[to] = from; //右边顶点to匹配到的左边顶点更新为from
//from找到匹配了，向前迭代，之前匹配的tmp_v给pre[from]
from = pre[from];
to = tmp_v; //from原来的匹配
}
while (!q.empty()) q.pop();
goto NEXT;
}
}
} //for auto it
} //while (!q.empty())
NEXT:
if (left_matching[v] != NOT_A_VERTEX) continue; //v找到了匹配，继续
else {
//v无法匹配到床位
result = false;
break;
}
} //for v
free(left_matching);
free(pre);
free(right_matching);
free(visited);
return result;
}
//输入一字节
void inputByte(byte* p_byte) {
int in;
scanf("%d", &in);
*p_byte = in;
}
void inputBoolean(bool * p_bool) {
int in;
scanf("%d", &in);
if (in) *p_bool = true;
else *p_bool = false;
}
int main() {
byte t, n, i, j, k;
inputByte(&t);
for (i = 0; i < t; i++) {
inputByte(&n);
Person * p = new Person[n];
for (j = 0; j < n; j++) inputBoolean(&p[j].is_student);
for (j = 0; j < n; j++) inputBoolean(&p[j].go_home);
for (j = 0; j < n; j++) {
if (p[j].is_student && !p[j].go_home) p[j].list.push_back(j); //若在校且不回家，可以睡自己的床
bool know_each_other;
for (k = 0; k < n; k++) {
inputBoolean(&know_each_other);
if (know_each_other && !(p[j].is_student && p[j].go_home) && p[k].is_student) { //j认识k且j在学校住且k是在校生，j可以睡k的床
p[j].list.push_back(k);
}
} //for k
} //for j
hungarian(p, n) ? printf("^_^\n") : printf("T_T\n");
for (j = 0; j < n; j++) {
p[j].~Person();
}
} //for i
return 0;
}