Submission #1334602

#	Time	Username	Problem	Language	Result	Execution time	Memory
1334602		retarde	Group Photo (JOI21_ho_t3)	C++20	44 / 100	5093 ms	440 KiB

Main

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

#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define int long long
#define all(x) (x).begin(), (x).end()

typedef long double ld;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;
typedef vector<vector<ll>> vvll;
typedef vector<string> vs;
typedef vector<vector<string>> vvs;
typedef vector<char> vc;
typedef vector<vector<char>> vvc;
typedef map<int, int> mii;
typedef unordered_map<int, int> umii;

const int mod = 1e9 + 7;
const int inf = INTMAX_MAX;
const bool tc = false;

int n; const int mxn = 5003;
int dp[mxn], a[mxn], pos[mxn + 1];

int cost(int x, int y) {
    // x < y
    // add from x + 1 to y, pos[i] - cntbefore[1,x]
    bool dbg = false;
    // if (x == 0 && y == 3) dbg = true;
    if (max(x, y) > n) return (int)0;
    int ans = 0;
    for (int i = x + 1; i <= y; i++) {
        int bfr = 0;
        for (int j = 0; j < pos[i]; j++) if (a[j] <= x || (a[j] > i && a[j] <= y)) bfr++;
        // for (int j = 1; j <= x; j++) if (pos[j] < pos[i]) bfr++;
        if (dbg) cout << i << " is i and " << pos[i] << " " << bfr << '\n';
        ans += pos[i] - bfr;
    }
    if (dbg) cout << ans << " ans\n";
    return ans;
}

inline void solve() {
    cin >> n; for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) {pos[a[i]] = i; dp[i] = 1e18; dp[i + 1] = 1e18;}
    dp[1] = pos[1]; dp[0] = 0;
    for (int i = 2; i <= n; i++) {
        for (int j = i - 1; j >= 0; j--) {
            dp[i] = min(dp[i], dp[j] + cost(j, i));
        }
    }
    // for (int i = 1; i <= n; i++) cout << dp[i] << " ";
    // cout << '\n';
    cout << dp[n] << '\n';
}

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

signed main() {
    ios::sync_with_stdio(false);
    cout.tie(0);
    cin.tie(0);
    //setIO();

    int t = 1;
    if (tc) {
        cin >> t;
    }

    while (t--) {
        solve();
    }
}

Compilation message (stderr)

Main.cpp: In function 'void setIO(std::string)':
Main.cpp:69:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:70:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36