【历年CSP-S复赛第一题】暴力解法与正解合集（2019-2022）

1. P5657 [CSP-S2019] 格雷码
2. P7076 [CSP-S2020] 动物园
3. P7913 [CSP-S 2021] 廊桥分配
4. P8817 [CSP-S 2022] 假期计划

P5657 [CSP-S2019] 格雷码

暴力50分

#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0) 
#define int long long
#define PII pair<int,int> 
#define pb push_back
using namespace std;
const int N = 1e6+5;
int n,k;
signed main()
{IOS;cin>>n>>k;vector<string> v;v.pb("0");v.pb("1");for(int j=1;j<=n-1;j++) {vector<string> vt;for(int i=0;i<(int)v.size();i++){vt.pb("0"+v[i]);}for(int i=(int)v.size()-1;i>=0;i--){vt.pb("1"+v[i]);}v = vt;}cout<<v[k];
}

正解

#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0) 
#define int long long
#define PII pair<int,int> 
#define pb push_back
using namespace std;
const int N = 1e6+5;
unsigned long long n,k;
signed main()
{IOS;cin>>n>>k;__int128 sum = (__int128)pow(2,n);int pre = -1;while(1){if(pre==-1){if(k<=sum/2-1){cout<<0;pre = -1;}else{cout<<1;pre = 1;k -= sum/2;}	}else{if(k<=sum/2-1)//k下标从1开始 {cout<<1;pre = -1;}else{cout<<0;pre = 1;k -= sum/2;}}sum /= 2;if(sum==1) break;}
}

P7076 [CSP-S2020] 动物园

暴力

#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0) 
#define int long long
#define PII pair<int,int> 
#define pb push_back
using namespace std;
const int N = 1e6+5;
int n,m,c,k;
int limit[N],va[N];
signed main()
{IOS;cin>>n>>m>>c>>k;for(int i=1;i<=n;i++) cin>>va[i];while(m--){int a,b;cin>>a>>b;limit[a] = b;//动物编号第a为1就必须有b号饲料 }set<int> s;for(int i=1;i<=n;i++)//由已有动物来倒推我有哪些饲料{for(int j=0;j<=k-1;j++){if((va[i]>>j)&1)//动物编号的二进制第j位为1 {s.insert(limit[j]);//动物编号的二进制第j位为1,即需要limit[j]号饲料}}}int sum = 0;for(int i=0;i<=pow(2,k)-1;i++){int suc = 1;for(int j=0;j<=k-1;j++){if((i>>j)&1){if(limit[j]==0) continue;if(s.count(limit[j])) continue;suc = 0;}}if(suc==1) sum++;}cout<<sum-n;
}

正解

#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0) 
#define int long long
#define PII pair<int,int> 
#define pb push_back
using namespace std;
const int N = 1e6+5;
int n,m,c,k;
int limit[N],va[N];
bool vis[N];
signed main()
{IOS;cin>>n>>m>>c>>k;for(int i=1;i<=n;i++) cin>>va[i];while(m--){int a,b;cin>>a>>b;limit[a] = b;//动物编号第a为1就必须有b号饲料 }for(int j=0;j<=k-1;j++){if(limit[j]==0) vis[j] = 1;for(int i=1;i<=n;i++){if((va[i]>>j)&1) vis[j] = 1;//由已有动物来倒推我哪些位置有哪些饲料}}int sum = 0;for(int i=0;i<=k-1;i++){if(vis[i]==1) sum++;}if(sum==64){if(n==0) cout<<"18446744073709551616";else cout<<(1ull<<(sum-1))-n+(1ull<<(sum-1));}else cout<<(1ull<<sum)-n;
}

P7913 [CSP-S 2021] 廊桥分配

暴力

#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0) 
#define int long long
#define PII pair<int,int> 
#define pb push_back
using namespace std;
const int N = 1e6+5;
int n,m1,m2;
struct node{int in;int out;
}va[N],vb[N];
bool cmp(node a,node b)
{return a.in<b.in;
}
int solve(int sum1,int sum2)
{int ans = 0;priority_queue <int,vector<int>,greater<int> > q1,q2;for(int i=1;i<=m1;i++) { while(q1.size()&&q1.top()<=va[i].in) q1.pop();if(q1.size()<sum1){ans++;q1.push(va[i].out);}}for(int i=1;i<=m2;i++) { while(q2.size()&&q2.top()<=vb[i].in) q2.pop();if(q2.size()<sum2){ans++;q2.push(vb[i].out);}}return ans;
}
signed main()
{IOS;cin>>n>>m1>>m2;int maxn = 0;for(int i=1;i<=m1;i++){cin>>va[i].in>>va[i].out;}for(int i=1;i<=m2;i++){cin>>vb[i].in>>vb[i].out;}sort(va+1,va+1+m1,cmp);sort(vb+1,vb+1+m2,cmp);for(int i=0;i<=n;i++){maxn = max(maxn,solve(i,n-i));}cout<<maxn;
}

正解

#include<bits/stdc++.h>
#define PII pair<int,int>
#define fi first
#define se second
#define int long longusing namespace std;const int N = 1e5+10;int n,m1,m2;
PII va[N],vb[N];
int cnt1[N],cnt2[N];priority_queue<PII,vector<PII>,greater<PII>> q1,q2;int solve1()
{for(int i=1;i<=n;i++) q1.push({0,i});for(int i=1;i<=m1;i++){int min_id = 1e9;vector<PII > v;while(q1.size()&&q1.top().fi<=va[i].fi){v.push_back(q1.top());if(min_id>q1.top().se) min_id = q1.top().se;q1.pop();}for(auto t:v){if(t.se==min_id) q1.push({va[i].se,t.se});else q1.push({0,t.se});}if(min_id!=1e9) cnt1[min_id]++;}for(int i=1;i<=n;i++) cnt1[i] = cnt1[i]+cnt1[i-1];
}int solve2()
{for(int i=1;i<=n;i++) q2.push({0,i});for(int i=1;i<=m2;i++){int min_id = 1e9;vector<PII > v;while(q2.size()&&q2.top().fi<=va[i].fi){v.push_back(q2.top());if(min_id>q2.top().se) min_id = q2.top().se;q2.pop();}for(auto t:v){if(t.se==min_id) q2.push({va[i].se,t.se});else q2.push({0,t.se});}if(min_id!=1e9) cnt2[min_id]++;}for(int i=1;i<=n;i++) cnt2[i] = cnt2[i]+cnt2[i-1];
}signed main()
{
//	freopen("w.in","r",stdin);
//  freopen("ho.out","w",stdout);cin>>n>>m1>>m2;for(int i=1;i<=m1;i++) cin>>va[i].fi>>va[i].se;for(int i=1;i<=m2;i++) cin>>vb[i].fi>>vb[i].se;sort(va+1,va+1+m1);sort(vb+1,vb+1+m2);solve1();solve2();int anw = 0;for(int i=0;i<=n;i++) anw = max(anw,cnt1[i]+cnt2[n-i]);cout<<anw;return 0;
}