Submission #1026385

#TimeUsernameProblemLanguageResultExecution timeMemory
1026385MardonbekhazratovRadio Towers (IOI22_towers)C++17
4 / 100
4072 ms2532 KiB
#include "towers.h"

#include <vector>
#include <algorithm>
#include <iostream>
#include <map>
#include <set>

using namespace std;

struct SegTree{
    int N;
    vector<int>tree;

    int merge(int a,int b){
        return max(a,b);
    }

    void build(int n){
        N=1;
        while(N<n) N<<=1;
        
        tree.assign(2*N,0);
    }

    void update(int v,int l,int r,int id,int x){
        if(r-l==1){
            tree[v]=x;
            return;
        }
        int mid=(l+r)/2;
        if(id<mid) update(v<<1,l,mid,id,x);
        else update(v<<1|1,mid,r,id,x);
        tree[v]=merge(tree[v<<1],tree[v<<1|1]);
    }

    void update(int id,int x){
        return update(1,0,N,id,x);
    }

    int get(int v,int l,int r,int ql,int qr){
        if(ql>=r || l>=qr) return 0;
        if(l>=ql && qr>=r) return tree[v];

        int mid=(l+r)/2;
        return merge(get(v<<1,l,mid,ql,qr),get(v<<1|1,mid,r,ql,qr));
    }

    int get(int l,int r){
        return get(1,0,N,l,r);
    }
};

int n,k;
vector<int>h;
bool su1=true;


void init(int N, std::vector<int> H) {
    n=N;
    h=H;
    k=0;
    bool ok=true;
    for(int i=1;i<n;i++){
        if(h[i]>h[i-1] && ok) k=i;
        else{
            if(h[i]>h[i-1]) su1=false;
            ok=false;
        }
    }
}

int max_towers(int L, int R, int D) {
    if(su1){
        if(L<k && R>k && h[k]-D>=h[L] && h[k]-D>=h[R]) return 2;
        return 1;
    }
    vector<int>a,dp(R-L+1);
    dp[0]=1;
    for(int i=L;i<=R;i++){
        a.push_back(h[i]);
    }
    
    // map<int,int>mp;
    // vector<int>b=a;
    // sort(b.begin(),b.end());
    // int c=0;
    // for(int x:b) m[x]=c++;
    // SegTree S;
    // S.build(c);
    
    int ans=1,mx=0;
    set<pair<int,int>>s={{a[0],0}};
    for(int i=1;i<a.size();i++){
        dp[i]=mx;
        dp[i]++;
        ans=max(ans,dp[i]);
        s.insert({a[i],i});
        while(a[i]-D>=(*s.begin()).first){
            auto x=*s.begin();
            mx=max(mx,dp[x.second]);
            s.erase(s.begin());
        }
    }
    return ans;
}

Compilation message (stderr)

towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:94:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   94 |     for(int i=1;i<a.size();i++){
      |                 ~^~~~~~~~~
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