Submission #786670

#	Time	Username	Problem	Language	Result	Execution time	Memory
786670		1bin	Group Photo (JOI21_ho_t3)	C++14	100 / 100	186 ms	67448 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#define all(v) v.begin(), v.end()
typedef long long ll;
const int NMAX = 5005;
int n, h[NMAX], ix[NMAX], big[NMAX], cnt[NMAX][NMAX], dp[NMAX];

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n;
    for(int i = 1; i <= n; i++) cin >> h[i], ix[h[i]] = i;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j < i; j++)
            if(h[j] > h[i]) big[h[i]]++;
    for(int i = 1; i <= n; i++)
        for(int j = i - 1; j; j--)
            cnt[i][j] = cnt[i][j + 1] + (ix[j] < ix[i]);

    memset(dp, 0x3f, sizeof(dp));
    dp[0] = 0;
    for(int i = 1; i <= n; i++){
        int cur = dp[i - 1];
        for(int j = i; j <= n; j++){
            cur += big[j] + 2 * cnt[j][i] - j + i;
            dp[j] = min(dp[j], cur);
        }
    }
    cout << dp[n];
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 20 / 20
• Subtask 5: 36 / 36