2022牛客寒假算法基础集训营4 ABCDEFGHIJKL

Posted 2022-02-18 quinn18

文章目录

• A R 模拟
• B 进制 线段树
• C 蓝彗星
• D 雪色光晕
• E 真假签到题
• F 小红的记谱法
• G 子序列权值乘积
• H 真真真真真签到题
• I 爆炸的符卡洋洋洒洒
• J 区间合数的最小公倍数
• K 小红的真真假假签到题题
• L 在这冷漠的世界里光光哭哭【待补】
• 总结

比赛链接

---

A R 模拟

题目链接
题意：

题解：

不包括 $P$ 就分段来计算
至少包含 $k$ 个 $R$
答案就等于这个位置前面第 k 个 $R$ 位置

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=2e5+5;
int a[N], p[N];
signed main() 
    int n, k; cin>>n>>k;
    string s; cin>>s;
    s=s+"P";
    int cnt=0;
    a[0]=-1;
	for (int i=0; i<=n; i++) 
		if(s[i]=='P') a[++cnt]=i;
	
	int ans=0; 
	for(int j=1; j<=cnt; j++)  
		int cntt=0;
		p[0]=0;
		for (int i=a[j-1]+1; i<a[j]; i++) 
			if (s[i]=='R') p[++cntt]=i+1-a[j-1]-1;
			if(cntt>=k) ans+=p[cntt-k+1];
		
	
	cout<<ans<<endl;
    return 0;

B 进制 线段树

题目链接
题意：

题解：

这个求和的bug真的找了一万年呜呜呜

#include<bits/stdc++.h>
#define int long long
#define ll long long
using namespace std;
const int N=1e5+5;
const int M=1e9+7;
int a[N];
int b[13][N];
int n, q;
int p[13][N];
int maxx[4*N];
int sum[13][4*N];
ll ksm(ll a,ll p)ll res=1;while(p)if(p&1)res=res*a%M;a=a*a%M;p>>=1;return res;
void pushup(int id) 
    maxx[id] = max(maxx[id << 1], maxx[id << 1 | 1]);

void build(int id, int l, int r) 
    if (l == r) 
        maxx[id] = a[l];
        return;
    
    int mid = (l + r) >> 1;
    build(id << 1, l, mid);
    build(id << 1 | 1, mid + 1, r);
    pushup(id);

void update(int id, int l, int r, int x, int v) 
    if (l == r) 
        maxx[id] = v;
        return;
    
    int mid = (l + r) >> 1;
    if (x <= mid) 
        update(id << 1, l, mid, x, v);
     else 
        update(id << 1 | 1, mid + 1, r, x, v);
    
    pushup(id);

int query(int id, int l, int r, int x, int y) 
    if(x<=l&&r<=y) 
        return maxx[id];
    
    int mid=(l+r)>>1;
    int ans=0;
    if(x<=mid) 
        ans=max(ans, query(id<<1, l, mid, x, y));
    
    if(y>mid) 
        ans=max(ans, query(id<<1|1, mid+1, r, x, y));
    
    return ans;

void pushup1(int id, int jin) 
    sum[jin][id] = (sum[jin][id << 1]+sum[jin][id << 1 | 1])%M;

void build1(int id, int l, int r, int jin) 
    if (l == r) 
        sum[jin][id] = b[jin][l]%M;
        return;
    
    int mid = (l + r) >> 1;
    build1(id << 1, l, mid, jin);
    build1(id << 1 | 1, mid + 1, r, jin);
    pushup1(id, jin);

void update1(int id, int l, int r, int x, int v, int jin) 
    if (l == r) 
        sum[jin][id] = v%M;
        return;
    
    int mid = (l + r) >> 1;
    if (x <= mid) 
        update1(id << 1, l, mid, x, v,jin);
     else 
        update1(id << 1 | 1, mid + 1, r, x, v,jin);
    
    pushup1(id, jin);

int query1(int id, int l, int r, int x, int y,int jin) 
    if(x<=l&&r<=y) 
        return sum[jin][id]%M;
    
    int mid=(l+r)>>1;
    int ans=0;
    if(x<=mid) 
        ans=ans%M+query1(id<<1, l, mid, x, y,jin)%M;
    
    if(y>mid) 
        ans=ans%M+query1(id<<1|1, mid+1, r, x, y,jin)%M;
    
    ans%=M;
    return ans;

signed main() 
    cin>>n>>q;
    string s;
    cin>>s;
    s='.'+s;
    for(int i=n; i>=1; i--) 
        a[i]=(s[i]-'0');
    
    for(int i=n; i>=1; i--) 
        for(int j=2; j<=10; j++) 
                b[j][i]=a[i]*ksm(j, n-i)%M;
                //cout<<i<<" "<<j<<" "<<b[j][i]<<endl;
        
    
    build(1, 1, n);
    for(int i=2; i<=10; i++) build1(1, 1, n, i);
    //cout<<"$$$"<<query1(1,1,n,1 ,3, 10)<<endl;
    while(q--) 
        int op, x, y;
        cin>>op>>x>>y;
        if(op==1) 
            update(1, 1, n, x, y);
            for(int i=2; i<=10; i++) update1(1, 1, n, x, y*ksm(i, n-x), i);
        else 
            int dang=query(1, 1, n, x, y);
            if(dang==0) cout<<0<<endl;
            else 
                dang++;
                cout<<query1(1,1,n,x, y,dang)%M*ksm(ksm(dang, n-y), M-2)%M<<endl;
            
        
    
    return 0;

C 蓝彗星

题目链接
题意：
题解：

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=2e5+5;
int a[N], b[N], c[N];
signed main() 
    int n, t;
    cin>>n>>t;
    string s;
    cin>>s;
    s='.'+s;
    for(int i=1; i<=n; i++) 
        int x; cin>>x;
        if(s[i]=='B') b[x]++, b[x+t]--;
        else c[x]++, c[x+t]--;
    
    for(int i=1; i<=N; i++) 
        b[i]+=b[i-1];
        c[i]+=c[i-1];
        //cout<<i<<" "<<b[i]<<" "<<c[i]<<endl;
    
    int ans=0;
    for(int i=1; i<=N; i++) 
        if(b[i]&&!c[i]) ans++;
    
    cout<<ans<<endl;
    return 0;

D 雪色光晕

题目链接
题意：

题解：

#include<bits/stdc++.h>
#define int long long
#define ll long long
using namespace std;
const int N=2e5+5;
const int M=1e9+7;
double dis(double xx, double yy, double x1, double y2) 
    return sqrt((xx-x1)*(xx-x1)+(yy-y2)*(yy-y2));

double Pd(double x, double y, double x1, double y1, double x2, double y2)
    double cross = (x2 - x1) * (x - x1) + (y2 - y1) * (y - y1);
    if (cross <= 0) return sqrt((x - x1) * (x - x1) + (y - y1) * (y - y1));
    double d2 = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1);
    if (cross >= d2) return sqrt((x - x2) * (x - x2) + (y - y2) * (y - y2));
    double r = cross / d2;
    double px = x1 + (x2 - x1) * r;
    double py = y1 + (y2 - y1) * r;
    return sqrt((x - px) * (x - px) + (py - y) * (py - y));

signed main() 
    int n;
    cin>>n;
    double x0, y0, X, Y;
    cin>>x0>>y0>>X>>Y;
    double minn=dis(x0,y0,X,Y);
    for(int i=1; i<=n; i++) 
        double x, y;
        cin>>x>>y;
        minn=min(minn, Pd(X, Y, x0,y0, x0+x, y0+y));
        x0+=x;
        y0+=y;
    
    cout<<fixed<<setprecision(8)<<minn<<endl;
    return 0;

E 真假签到题

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