Submission #1282273

#	Time	Username	Problem	Language	Result	Execution time	Memory
1282273		quan606303	Building Bridges (CEOI17_building)	C++20	0 / 100	3096 ms	33176 KiB

building

/*
 * @Author: RMQuan 
 * @Date: 2025-10-22 23:48:40 
 * @Last Modified by: RMQuan
 * @Last Modified time: 2025-10-23 01:57:18
 */
/*idea : 



*/
#include <bits/stdc++.h>
bool M1;
#define ll long long
#define INTMAX INT_MAX
#define INTMIN INT_MIN
#define LONGMAX LLONG_MAX
#define LONGMIN LLONG_MIN
#define fi first
#define se second
#define memfull(a,b) memset(a,b,sizeof(a));
#define endl '\n'
#define TASK "TEST"
#define file() if (fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin); freopen(TASK".out","w",stdout);}
using namespace std;
const int MOD=1e9+7;
const int maxn=1e5+7;
const int LOG=16;
const int inf=1e9;
int a[maxn],n,k;
int rmq[maxn][LOG+1];
struct query
{
    int pos,val,type;
};
bool cmp(const query &x,const query &y)
{
    if (x.pos!=y.pos)return x.pos<y.pos;
    return x.type<y.type;
}
void build(const vector<pair<int,pair<int,int>>> &qr)
{
    for (int i=0;i<=n;i++) rmq[i][0]=inf;

    vector<query> vt;
    vector<int> vals;
    for (auto &i: qr){
        vt.push_back({i.se.fi, i.fi, 1});
        vt.push_back({i.se.se+1, i.fi, -1});
        vals.push_back(i.fi);
    }
    for (int i=0;i<=n;i++) vt.push_back({i,0,2});
    sort(vt.begin(), vt.end(), cmp);

    // nén giá trị
    sort(vals.begin(), vals.end());
    vals.erase(unique(vals.begin(), vals.end()), vals.end());
    int m = vals.size();
    auto id = [&](int x){ return (int)(lower_bound(vals.begin(), vals.end(), x) - vals.begin()) + 1; };

    vector<int> bit(m+5, 0);

    auto add=[&](int i,int v){
        for (;i<=m;i+=i&-i) bit[i]+=v;
    };
    auto sum=[&](int i){
        int s=0;
        for (;i>0;i-=i&-i) s+=bit[i];
        return s;
    };
    auto find_first=[&](){
        if (sum(m)==0) return inf;
        int pos=0;
        for (int pw=(1<<20);pw;pw>>=1){
            if (pos+pw<=m && bit[pos+pw]==0){
                pos+=pw;
            }else if (pos+pw<=m && bit[pos+pw]<0){
                pos+=pw;
            }
        }
        // find first with prefix sum >=1
        int l=1,r=m,res=m;
        while(l<=r){
            int mid=(l+r)/2;
            if (sum(mid)>=1) res=mid,r=mid-1;
            else l=mid+1;
        }
        return vals[res-1];
    };

    for (auto &q: vt){
        if (q.type==1){
            add(id(q.val),1);
        }
        else if (q.type==-1){
            add(id(q.val),-1);
        }
        else{
            rmq[q.pos][0]=find_first();
        }
    }

    for (int j=1;j<=LOG;j++)
        for (int i=0;i+(1<<j)-1<=n;i++)
            rmq[i][j]=min(rmq[i][j-1], rmq[i+(1<<(j-1))][j-1]);
}

int get(int l,int r)
{
    int k=__lg(r-l+1);
    return min(rmq[l][k],rmq[r-(1<<k)+1][k]);
}
int L[maxn],R[maxn];
int dp[maxn];
int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    file();
    cin>>n>>k;
    for (int i=1;i<=n;i++)cin>>a[i];  
    stack<int> st;
    for (int i=1;i<=n;i++)
    {
        while (st.size()&&a[st.top()]<=a[i])st.pop();
        if (st.size())L[i]=st.top()+1;
        else L[i]=1;
        st.push(i);
    }
    while (st.size())st.pop();
    for (int i=n;i>=1;i--)
    {
        while(st.size()&&a[st.top()]<=a[i])st.pop();
        if (st.size())R[i]=st.top()-1;
        else R[i]=n;
        st.push(i);
    }
    vector<pair<int,pair<int,int> > >qr;
    qr.push_back({0,{0,0}});
    build(qr);
    for (int j=1;j<=k;j++)
    {
        qr.clear();
        for (int i=1;i<=n;i++)
        {
            int l=L[i]-1;
            int r=i-1;
            int u=i;
            int v=R[i];
            int val=get(l,r);
            qr.push_back({val+a[i],{u,v}});
            cerr<<val+a[i]<<" "<<u<<" "<<v<<endl;
        }
        build(qr);
    }
    cout<<get(n,n);
    bool M2;
    cerr<<"-------------------------------------------------"<<endl;
    cerr<<"Time : "<<clock()<<" ms"<<endl;
    cerr<<"Memory : "<<abs(&M2-&M1)/1024/1024<<" MB"<<endl;
    cerr<<"-------------------------------------------------"<<endl;
    return 0;
}

Compilation message (stderr)

building.cpp: In function 'int32_t main()':
building.cpp:24:50: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 | #define file() if (fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin); freopen(TASK".out","w",stdout);}
      |                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
building.cpp:120:5: note: in expansion of macro 'file'
  120 |     file();
      |     ^~~~
building.cpp:24:81: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 | #define file() if (fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin); freopen(TASK".out","w",stdout);}
      |                                                                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
building.cpp:120:5: note: in expansion of macro 'file'
  120 |     file();
      |     ^~~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40