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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#579333 | #7900. Gifts from Knowledge | Master640 | RE | 22ms | 105952kb | C++14 | 3.1kb | 2024-09-21 12:28:40 | 2024-09-21 12:28:42 |
Judging History
answer
//
// Created by 35263 on 2024/9/20.
//
//每次选择是否反转一行,每一行最多进行一次反转,只有转和不转两种情况
//观察到r*c这是一个矩阵
//感觉像是一个dp
//给定相同相反关系,求方案数的题目,那么就必然是建图解决
//决定做就去做
//二分图染色 3 - color[x]
//连线+二分图染色说明两个不能同时选
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1000005;
const ll mod = 1e9 + 7;
string str[maxn];
int n,m,cnt[maxn],vis[maxn*2];
vector<int>pos[maxn],g[maxn*2];
//有意识地去突破
//i代表第i行不反转,i+n代表第i行反转
//所以连接的话,如果1都在第j列,那么(i->i'+n,i'->i+n);
//如果两个1不在同一列,那么(i->i',i+n->i’+n);
//最后普dfs一遍计算连通块个数,ksm一下即可
ll ksm(int x,int b){
ll ans=1;
while(b){
if(b&1)ans=(ans*x)%mod;
b>>=1;
x=(x*x)%mod;
}
return ans;
}
void update(){
for(int i=1;i<=m;i++)pos[i].clear(),cnt[i]=0;
for(int i=1;i<=2*n;i++)g[i].clear();
for(int i=1;i<=2*n;i++)vis[i]=0;
}
void add(int x,int y){
g[x].push_back(y);g[y].push_back(x);
}
int get_color(int x){
for(auto v:g[x]){
if(vis[v]) {
if (vis[v] == vis[x])return false;
}
else {
vis[v] = 3 - vis[x];
get_color(v);
}
}
return true;
}
void init(){
cin>>n>>m;
update();
for(int i=1;i<=n;i++)cin>>str[i],str[i]=" "+str[i];
for(int i=1;i<=m;i++){
for(int j=1;j<=n;j++){
if(str[j][i]=='1') {
cnt[i] += (str[j][i] == '1');
pos[i].push_back(j);
}
}
}
int flag=true;
for(int i=1;i<=(m+1)/2;i++){
if(i==m-i+1){
if(cnt[i]>1){
flag=false;
break;
}
continue;
}
if(cnt[i]+cnt[m-i+1]>2){
flag=false;
break;
}
}
if(!flag){
cout<<0<<endl;
return;
}
for(int i=1;i<=n;i++)add(i,i+n);
for(int i=1;i<=(m+1)/2;i++){
if(i==m-i+1)continue;
if(pos[i].size()==2){
int u=pos[i][0],v=pos[i][1];
add(u,v);add(u+n,v+n);
}
else{
if(pos[i].size()==1){
int u=pos[i][0],v=pos[m-i+1][0];
add(u,v+n);add(v,u+n);
}
else{
int u=pos[m-i+1][0],v=pos[m-i+1][1];
add(u,v);add(u+n,v+n);
}
}
}
int cnt_blocks=0;
flag=true;
for(int i=1;i<=2*n;i++){
if(!vis[i]){
vis[i]=1;
if(get_color(i))cnt_blocks++;
else flag=false;
}
}
// cout<<cnt_blocks<<endl;
if(flag)
cout<<ksm(2,cnt_blocks)%mod<<endl;
else
cout<<0<<endl;
}
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
int t;
cin>>t;
while(t--){
update();
init();
}
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 22ms
memory: 105952kb
input:
3 3 5 01100 10001 00010 2 1 1 1 2 3 001 001
output:
4 0 2
result:
ok 3 number(s): "4 0 2"
Test #2:
score: -100
Runtime Error
input:
15613 10 10 0000000000 0000000000 0000000000 0000000000 0000000000 0000000000 0000000000 0000000000 0000000000 0000000000 15 8 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 1 5 00000 5 9 000000000 000000000 0000...