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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#180301 | #5423. Perfect Matching | Zhou_JK | RE | 0ms | 0kb | C++23 | 2.1kb | 2023-09-15 17:56:56 | 2023-09-15 17:56:57 |
answer
#include<iostream>
#include<cstdio>
#include<cassert>
#include<vector>
#include<unordered_map>
using namespace std;
const int N=100005;
const long long INF=4557430888798830399;
int n;
int a[N];
int tot;
vector<pair<long long,int>>G[N*2];
int match[N];
bool vis[N*2];
void dfs(int u,int father,int pre)
{
vis[u]=true;
vector<int>edge;
for(auto [v,i]:G[u])
{
if(v==father) continue;
if(vis[v]) continue;
dfs(v,u,i);
}
for(auto [v,i]:G[u])
if(i!=pre)
{
if(!match[i]) edge.emplace_back(i);
}
if(edge.size()%2==1) edge.emplace_back(pre);
for(int i=0;i<(int)edge.size();i+=2)
{
// cerr<<"now"<<u<<" "<<edge[i]<<" "<<edge[i+1]<<"\n";
assert(edge[i]!=edge[i+1]);
if(edge[i+1]) assert(abs(edge[i]-edge[i+1])==abs(a[edge[i]]-a[edge[i+1]]));
match[edge[i]]=edge[i+1],match[edge[i+1]]=edge[i];
}
return;
}
void solve()
{
cin>>n;
for(int i=1;i<=n;i++)
cin>>a[i];
unordered_map<int,int>pos;
tot=0;
for(int i=1;i<=n;i++)
{
if(!pos.count(i-a[i])) pos[i-a[i]]=++tot;
if(!pos.count(i+a[i]+INF)) pos[i+a[i]+INF]=++tot;
}
for(int i=1;i<=tot;i++)
G[i].clear(),vis[i]=false;
for(int i=1;i<=n;i++)
match[i]=0;
for(int i=1;i<=n;i++)
G[pos[i-a[i]]].emplace_back(pos[i+a[i]+INF],i),G[pos[i+a[i]+INF]].emplace_back(pos[i-a[i]],i);//cerr<<pos[i-a[i]]<<" "<<pos[i+a[i]+INF]<<" "<<i<<"\n";
for(int i=1;i<=tot;i++)
if(!vis[i])
{
dfs(i,0,0);
if(match[0])
{
cout<<"No\n";
return;
}
}
cout<<"Yes\n";
for(int i=1;i<=n;i++)
if(i<match[i]) cout<<i<<" "<<match[i]<<"\n";
return;
}
int main()
{
freopen("data.in","r",stdin);
freopen("data.out","w",stdout);
ios::sync_with_stdio(false);
cin.tie(nullptr),cout.tie(nullptr);
int T;
cin>>T;
while(T--)
solve();
return 0;
}
Details
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Test #1:
score: 0
Dangerous Syscalls
input:
3 6 14 22 33 11 25 36 4 100 10 98 12 4 1 3 5 7