Submission #1280742

#	Time	Username	Problem	Language	Result	Execution time	Memory
1280742		vuquangsang	Money (IZhO17_money)	C++20	100 / 100	988 ms	63072 KiB

money

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

#define     el "\n"
#define     FOR(i,a,b) for(int i = (a), _b = (b); i <= _b; i++)
#define     FORD(i,a,b) for(int i = (a), _b = (b); i >= _b; i--)
#define     pb push_back
#define     fi first
#define     se second
#define     all(x) x.begin(),x.end()
#define     lg(x) __lg(x)
#define     alla(a,n) a+1,a+n+1
#define     ll long long


template <class T> bool maxi(T &x, T y) { if(x < y) { x = y ; return true ;} return false;}
template <class T> bool mini(T &x, T y) { if(x > y) { x = y ; return true ;} return false;}

const int N = 1e6 + 2;
const int INF = 1e9 + 2;

int n, a[N];

void inp()
{
    cin >> n;
    FOR(i, 1, n) cin >> a[i];
}

/* Try your best
    No regrets */

namespace subtask_3
{

    int dp[N];
    void slv()
    {
        FOR(i, 1, n) dp[i] = INF;

        FOR(i, 1, n) {
            dp[i] = min(dp[i], dp[i - 1] + 1);

            FORD(j, i - 1, 1) {
                if(a[j] > a[j + 1]) break;
                bool ok = 1;
                FOR(t, 1, j - 1) {
                    if(a[j] < a[t] && a[t] < a[i]) ok = 0;
                }
                if(!ok) break;
                mini(dp[i], dp[j - 1] + 1);
            }
        }
        cout << dp[n];
    }
}

namespace subtask_4
{
    int left[N];
    int valLeft[N];
    int dp[N];

    void slv()
    {
        left[1] = 1;
        for(int i = 2; i <= n; i++) {
            left[i] = (a[i] >= a[i - 1] ? left[i - 1] : i);
        }

        set<int> S;
        a[0] = INF;
        valLeft[0] = INF;
        for(int i = 0; i < n; i++) {
            S.insert(a[i]);
            if(i > 0) valLeft[i] = *S.upper_bound(a[i + 1]);
        }

        for(int i = 1; i <= n; i++) dp[i] = INF;
        for(int i = 1; i <= n; i++) {
            int l = left[i], r = i, mid, pos = i;
            while(l <= r) {
                mid = (r + l) >> 1;
                if(valLeft[mid - 1] >= a[i]) pos = mid, r = mid - 1;
                else l = mid + 1;
            }

            dp[i] = dp[pos - 1] + 1;
        }
        cout << dp[n];
    }
}

/* Code slowly, think carefully */

main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    #define __Azul__ "money"
    if(fopen(__Azul__".inp", "r")) {
        freopen(__Azul__".inp", "r", stdin);
        freopen(__Azul__".out", "w", stdout);
    }

    bool qs = 0;

    int T = 1;
    if(qs) cin >> T;
    while(T--) {
        inp();
        subtask_4::slv();
    }

    cerr << "\nTime" << 0.001 * clock() << "s "; return 0;


}

Compilation message (stderr)

money.cpp:96:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   96 | main()
      | ^~~~
money.cpp: In function 'int main()':
money.cpp:102:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |         freopen(__Azul__".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
money.cpp:103:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  103 |         freopen(__Azul__".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 20 / 20
• Subtask 4: 55 / 55