Submission #1273836

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273836		icebear	Fire (BOI24_fire)	C++20	100 / 100	137 ms	17788 KiB

Main

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

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "gen"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
int n, m;
vector<ii> range;
int nxt[N][20];

void init(void) {
    cin >> n >> m;
    FOR(i, 1, n) {
        int L, R;
        cin >> L >> R;
        if (R < L) R += m;
        range.pb(mp(L, R));
    }
}

void process(void) {
    sort(all(range));

//    for(ii x : range) cerr << x.fi << ' ' << x.se << '\n';
    int j = 0, mxR = 0;
    REP(i, n) {
        maximize(j, i);
        while(j + 1 < n && range[i].se >= range[j + 1].fi) {
            j++;
            if (range[j].se >= range[mxR].se) mxR = j;
        }
//        cerr << i << ' ' << mxR << '\n';
        if (range[i].se >= range[mxR].fi) nxt[i][0] = mxR;
    }

    FOR(j, 1, 19) REP(i, n)
        nxt[i][j] = nxt[nxt[i][j - 1]][j - 1];

    auto jump = [&](int i, int k) {
        RED(j, 20) if (BIT(k, j))
            i = nxt[i][j];
        return i;
    };

    int low = 1, high = n, res = -1;
    while(low <= high) {
        int mid = (low + high) >> 1;
        bool ok = false;
        REP(i, n) {
            int j = jump(i, mid - 1);
            if (range[j].se - range[i].fi >= m) {
                ok = true;
                break;
            }
        }
        if (ok) res = mid, high = mid - 1;
        else low = mid + 1;
    }
    cout << res;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 13 / 13
• Subtask 5: 21 / 21
• Subtask 6: 26 / 26