牛客小白月赛22

牛客小白月赛22

水水水----放点稍微不水的

A.操作序列

模拟+stl
看着题意打就行，主要输入恶心，所以上榜了

#pragma GCC optimize(3,"Ofast","inline")  	//G++
#include<bits/stdc++.h>
#define TEST freopen("C:\\Users\\hp\\Desktop\\ACM\\in.txt","r",stdin);
#define mem(a,x) memset(a,x,sizeof(a))
#define debug(x) cout << #x << ": " << x << endl;
#define ios ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fcout cout<<setprecision(4)<<fixed
using namespace std;
typedef long long ll;
typedef pair<int,int> pi;


const int inf=0x3f3f3f3f;
const ll INF=0x7fffffffffffffff;
const int mod=1e9+7;
const int maxn = 1e6+5;
const double eps=1e-8;

template<typename T> void read(T &x) {
    x = 0;
    char ch = getchar();
    ll f = 1;
    while(!isdigit(ch)) {
        if(ch == '-')f*=-1;
        ch=getchar();
    }
    while(isdigit(ch)) {
        x = x*10+ch-48;
        ch=getchar();
    }
    x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}
int sgn(double a) {
    return a<-eps?-1:a<eps?0:1;
}
int num[105];
int get_cin(){
    string str;
    getline(cin,str);
    if(str[0]=='-')
        return -1;
    int n=str.size();
    int op=1,pos;
    for(int i=0;i<n;i++){
        if(str[i]==' ')
            op=2,pos=i;
    }
    if(op==1){
        num[1]=0;
        for(int i=0;i<n;i++){
            num[1]=num[1]*10+str[i]-'0';
        }
    }
    else{
        num[1]=num[2]=0;
        for(int i=0;i<pos;i++){
            num[1]=num[1]*10+str[i]-'0';
        }
        for(int i=pos+1;i<n;i++){
            num[2]=num[2]*10+str[i]-'0';
        }
    }
    return op;
}
set<int>s;
map<int,int>mp;
void solve(){
    int op=get_cin();
    if(op==2){
        int t=num[1],c=num[2];
//        auto it=s.lower_bound(t-30);
//        if(it==s.end()||*it>t+30){
//            s.insert(t);
//            mp[t]=c;
//        }
        if(c&&s.lower_bound(t-30)==s.upper_bound(t+30)){
            s.insert(t);
            mp[t]=c;
        }
    }
    else if(op==1){
        int t=num[1];
        cout<<mp[t]<<"\n";
    }
    else
    {
        if(s.size()==0){
            cout<<"skipped\n";
            return ;
        }
        cout<<mp[*s.begin()]<<"\n";
        mp[*s.begin()]=0;
        s.erase(s.begin());
    }
}
int main(){
    int T;
    scanf("%d",&T);
    getchar();
    while(T--)
        solve();

}

B

树的直径—树形DP

#pragma GCC optimize(3,"Ofast","inline")  	//G++
#include<bits/stdc++.h>
#define mem(a,x) memset(a,x,sizeof(a))
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pi;

const ll inf=0x3f3f3f3f;
const ll maxn = 1e6+5;

template<typename T> void read(T &x){
    x = 0;char ch = getchar();ll f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}

ll n, m;
ll ans=-1e15;
vector<ll> edge[maxn];
void add(ll x,ll y){
    edge[x].push_back(y);
    edge[y].push_back(x);
}
ll dp[maxn][2];// 0最长 1次长
ll a[maxn];
void dfs(ll u,ll fa){

    dp[u][0]  =a[u];
    dp[u][1] = -inf;
    for(auto v:edge[u]){
        if(v==fa) continue;
        dfs(v,u);
        if(dp[v][0]+a[u]>dp[u][0]) dp[u][1]=dp[u][0],dp[u][0]=dp[v][0]+a[u];
        else if(dp[v][0]+a[u]>dp[u][1])
            dp[u][1] = dp[v][0] + a[u];
    }
    ans = max(dp[u][0] + dp[u][1]-a[u], ans);
}
main()
{
    read(n);
    for (ll i = 1; i <= n;i++){
        read(a[i]);
        ans = max(a[i], ans);
        //   dp[i][0] = dp[i][1] = -inf;
    }
    for (ll i = 1; i <= n - 1; i++)
    {
        ll x, y;
        read(x, y);
        add(x, y);
    }
    dfs(1, 0);
    cout << ans << "\n";
}

C

所有状态预处理一遍即可

//#pragma GCC optimize(3,"Ofast","inline")  	//G++
//#include<bits/stdc++.h>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include <cstdlib>
#include <iomanip>
#define TEST freopen("C:\\Users\\hp\\Desktop\\ACM\\in.txt","r",stdin);
#define mem(a,x) memset(a,x,sizeof(a))
#define debug(x) cout << #x << ": " << x << endl;
#define ios ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fcout cout << setprecision(4) << fixed;
using namespace std;
typedef long long ll;
typedef pair<int,int> pi;


const int inf=0x3f3f3f3f;
const int mod=1e9+7;
const int maxn = 1e6+5;
const double eps=1e-8;

template<typename T> void read(T &x){
    x = 0;char ch = getchar();int f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}
int sgn(double a){
    return a<-eps?-1:a<eps?0:1;
}
int a[maxn],dp[maxn];
void dfs(int now,int pos){

    if(now==11){
        int sum = 0;
        for (int i = 1;i<=12;i++)
            sum = sum + (a[i]);
        dp[pos] = min(dp[pos], sum);
        return ;
    }
    dfs(now + 1,pos);
    if(a[now]==1&&a[now+1]==1&&a[now+2]==0){

        a[now] = 0, a[now + 1] = 0, a[now + 2] = 1;
        dfs(max(now-2,1) ,pos);
        a[now] = 1, a[now + 1] = 1, a[now + 2] = 0;
    }
    if(a[now]==0&&a[now+1]==1&&a[now+2]==1){
        a[now] = 1, a[now + 1] = 0, a[now + 2] = 0;
        dfs(max(now-2,1) ,pos);
        a[now] = 0, a[now + 1] = 1, a[now + 2] = 1;
    }
}
void init(){
    
    for (int i = 0;i<(1<<12);i++){
        for(int j=0,k=12;j<12;j++,k--){
            a[k] =((i >> j) & 1);
        }
        dp[i] = inf;
        dfs(1, i);
    }
}
char s[maxn];
void solve(){
    int sum = 0;
    scanf("%s", s + 1);
    for(int i=1;i<=12;i++){
        sum = sum * 2 + (s[i]=='o');
    }
    cout << dp[sum] << "\n";
}
int main(){
    init();
    int T;
    read(T);
    while(T--)
        solve();
}

D.dfs暴力 水题
F签到题 水题
G暴力 水题
H

区间合并+差分数组 好像还是水题

//#pragma GCC optimize(3,"Ofast","inline")      //G++
//#include<bits/stdc++.h>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include <cstdlib>
#include <iomanip>
#define TEST freopen("C:\\Users\\hp\\Desktop\\ACM\\in.txt","r",stdin);
#define mem(a,x) memset(a,x,sizeof(a))
#define debug(x) cout << #x << ": " << x << endl;
#define ios ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fcout cout << setprecision(4) << fixed;
using namespace std;
typedef long long ll;
typedef pair<int,int> pi;
 
 
const int inf=0x3f3f3f3f;
const int mod=1e9+7;
const int maxn = 1e6+5;
const double eps=1e-8;
 
template<typename T> void read(T &x){
    x = 0;char ch = getchar();int f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}
int sgn(double a){
    return a<-eps?-1:a<eps?0:1;
}
int n, m;
int d[maxn];
map<int,vector<pair<int, int> > > mp;
void add(int l,int r){
    d[l]++, d[r + 1]--;
}
void work(vector<pair<int,int> >v){
    sort(v.begin(), v.end());
    int l=maxn,r=-maxn;
    for(auto it:v){
        int ll = it.first;
        int rr = it.second;
        if(ll>r){
            if(l!=maxn){
                add(l, r);
            }
            l = ll, r = rr;
        }
        else{
            l=min(l,ll);
            r = max(r, rr);
        }
    }
    add(l, r);
}
void solve(){
    read(n, m);
    for (int i = 1; i <= n;i++){
        int l, r, dd;
        read(l, r, dd);
        mp[dd].push_back({l, r});
    }
    for(auto it:mp){
        work(mp[it.first]);
    }
    int ans, sum = 0;
    for (int i = 1;i<=n;i++){
        d[i] += d[i - 1];
        if(d[i]>sum){
            sum=d[i];
            ans = i;
        }
    }
    cout << ans << "\n";
}
int main(){
    solve();
}

I不会
J模拟—水题