제출 #1303873

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1303873		trandangquang	Discharging (NOI20_discharging)	C++20	9 / 100	95 ms	19936 KiB

Discharging

#include<bits/stdc++.h>
using namespace std;

#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define bit(s,i) (((s)>>(i))&1)
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<ii>
#define fi first
#define se second
#define ll long long
#define eb emplace_back
#define pb push_back
#define __builtin_popcount __builtin_popcountll
#define _ << " " <<

template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}

const int N=1e6+5;
const ll INF=1e18;

int n,t[N]; ll dp[N];
ii stk[N]; int top;
ll minDP[N];

struct Line{
    ll a,b;
    Line(ll _a=INF, ll _b=INF) : a(_a), b(_b) {}
    ll val(ll x){
        return a*x + b;
    }
};

struct Node{
    Line ln;
    int lc,rc;
    Node(){
        ln=Line();
        lc=rc=0;
    }
};
vector<Node> tr(2);
vector<pair<int,Line>> roll;

void upd(Line ln, int id=1, int l=1, int r=n){
    int mid=(l+r)>>1;
    if(ln.val(mid)<tr[id].ln.val(mid)){
        roll.eb(id,tr[id].ln);
        swap(ln,tr[id].ln);
    }

    if(l==r || ln.b==INF) return;
    if(ln.val(l)<tr[id].ln.val(l)){
        if(tr[id].lc==0) tr[id].lc=sz(tr), tr.eb();
        upd(ln,tr[id].lc,l,mid-1);
    } else{
        if(tr[id].rc==0) tr[id].rc=sz(tr), tr.eb();
        upd(ln,tr[id].rc,mid+1,r);
    }
}

ll get(int x, int id=1, int l=1, int r=n){
    if(tr[id].ln.b==INF) return INF;
    int mid=(l+r)>>1;
    return min(tr[id].ln.val(x), x<=mid ? get(x,tr[id].lc,l,mid-1) : get(x,tr[id].rc,mid+1,r));
}

void rollback(int x){
    while(sz(roll)>x){
        tr[roll.back().fi].ln=roll.back().se;
        roll.pop_back();
    }
}

void solve(){
    cin>>n;
    foru(i,1,n) cin>>t[i];

    memset(dp,0x3f,sizeof(dp));

    dp[n+1]=0;
    ford(i,n,1){
        minDP[i]=dp[i+1];
        while(top && t[stk[top].fi]<t[i]){
            mini(minDP[i], minDP[stk[top].fi]);
            --top;
        }
        rollback(stk[top].se);
        upd(Line(t[i],minDP[i]));
        ++top; stk[top]={i,sz(roll)};
        dp[i]=get(n-i+1);
    }
    cout<<dp[1]<<'\n';
}

int32_t main(){
    #define task "test"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    int tc=1; //cin>>tc;
    foru(i,1,tc){
        solve();
    }
}

컴파일 시 표준 에러 (stderr) 메시지

Discharging.cpp: In function 'int32_t main()':
Discharging.cpp:104:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Discharging.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 13
• Subtask 3: 0 / 25
• Subtask 4: 0 / 11
• Subtask 5: 0 / 14
• Subtask 6: 0 / 28