已经确认是判二分图这里写TLE了,但是这里应该是O(n+m)的时间复杂度来着,求救大佬们 用的是
https://www.cnblogs.com/dx123/p/16418198.html
这里的二分图判定
#include<bits/stdc++.h>
using namespace std;
int _;
#define p 1e9+7
const int N = 1e4 + 10;
struct node {
int v, ne;
}e[N];
int h[N];
int color[N];
int idx;
void add(int a, int b) {
e[++idx] = { b,h[a] };
h[a] = idx;
}
bool dfs(int u, int c) {//节点和颜色
color[u] = c;
for (int i = h[u]; i; i = e[i].ne) {
int v = e[i].v;
if (!color[v]) {
if (dfs(v, 3 - c)) {
return 1;
}
}
else if (color[v] == c) {
return 1;
}
}
return 0;
}
void solve() {
idx = 0;
int n, m; cin >> n >> m;
for(int i=1;i<=n;++i) color[i]=0;
for(int i=1;i<=n;++i) h[i]=0;
for(int i=1;i<=m;++i) e[i].v=0,e[i].ne=0;
for (int i = 1; i <= m; ++i) {
int x, y; cin >> x >> y;
add(x, y);
add(y, x);
}
bool flag=0;//0就是有二分图
for(int i=1;i<=n;++i){
if(!color[i]){
if(dfs(i,1)){
flag=1;
break;
}
}
}
if (flag) {//不存在二分图,alice随便赢
cout << "Alice" << endl;
for (int i = 1; i <= n; ++i) {
int x, y;
cout << 1 << ' ' << 2 << endl;
cin >> x >> y;
}
}
else {
vector<int> ac;
vector<int> bc;
for (int i = 1; i <= n; ++i) {
if (color[i] == 1) ac.push_back(i);
else bc.push_back(i);
}
cout << "Bob" << endl;
for (int q = 1; q <= n; ++q) {
int x, y;
cin >> x >> y;
if (x == 1 || y == 1) {
if (!ac.empty()) {
cout << *ac.rbegin() << " " << 1 << endl;
ac.pop_back();
continue;
}
}
if (x == 2 || y == 2) {
if (!bc.empty()) {
cout << *bc.rbegin() << " " << 2 << endl;
bc.pop_back();
continue;
}
}
if (ac.empty()) {
cout << *bc.rbegin() << " " << 3 << endl;
bc.pop_back();
}
else {
cout << *ac.rbegin() << " " << 3 << endl;
ac.pop_back();
}
}
}
}
signed main() {
ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
cin >> _;
while (_--) {
solve();
}
return 0;
}