Submission #1060873

#	Time	Username	Problem	Language	Result	Execution time	Memory
1060873		RiverFlow	Osumnjičeni (COCI21_osumnjiceni)	C++14	40 / 110	334 ms	104016 KiB

Main

#include <bits/stdc++.h>

#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())

using namespace std;

template<typename U, typename V> bool maxi(U &a, V b) {
    if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
    if (a > b or a == 0) { a = b; return 1; } return 0;
}

const int N = (int)2e5 + 9;
const int mod = (int)1e9 + 7;

void prepare(); void main_code();

int main() {
    ios::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);
    }
    const bool MULTITEST = 0; prepare();
    int num_test = 1; if (MULTITEST) cin >> num_test;
    while (num_test--) { main_code(); }
}

void prepare() {};

const int LG = 17;

int p[N], l[N], r[N], lg[N], sp[N][LG + 1];

int get(int l, int r) { int j = lg[r - l + 1];
    return min(sp[l][j], sp[r - (1 << j) + 1][j]);
}

int n;

namespace SUB1 {
    const int N = (int)5e3 + 3;

    int dp[N][N];

    void sol() {
        for(int i = 1; i <= n; ++i) {
            p[i] = n + 1;
            for(int j = i + 1; j <= n; ++j) {
                if ( l[i] > r[j] or r[i] < l[j] ) continue ;
                p[i] = j; break ;
            }
            sp[i][0] = p[i];
        }
        FOR(i, 2, n) lg[i] = lg[i / 2] + 1;
        for(int j = 1; (1 << j) <= n; ++j)
            for(int i = 1; i + (1 << j) - 1 <= n; ++i)
                sp[i][j] = min(sp[i][j - 1], sp[i + (1 << (j - 1))][j - 1]);

        FOD(i, n, 1) {
            int num_seg = 0;
            int last_end = i;
            dp[i][i] = 1;
            for(int j = i + 1; j <= n; ++j) {
                if (get(last_end, j) > j) {
                    dp[i][j] = num_seg + 1;
                    continue ;
                }
                ++num_seg;
                last_end = j;
                dp[i][j] = num_seg + 1;
            }
        }
        int q; cin >> q;
        while (q--) {
            int l, r; cin >> l >> r;
            cout << dp[l][r] << nl;
        }
    }
};

struct segment_tree {
    int n;
    vector<int> t, lz;
    const int INF = (int)1e8;
    segment_tree (int _n) {
        n = _n;
        t.resize(4 * n + 7);
        lz.resize(4 * n + 7);
        FOR(i, 1, 4 * n) t[i] = INF;
    }
    void upd(int id, int l, int r, int u, int v, int val) {
        if (l > v or r < u) return ;
        if (l >= u and r <= v) {
            t[id] = val;
            lz[id] = val;
            return ;
        }
        if (lz[id]) {
            mini(t[id << 1], lz[id]);
            mini(t[id << 1 | 1], lz[id]);
            mini(lz[id << 1], lz[id]);
            mini(lz[id << 1 | 1], lz[id]);
            lz[id] = 0;
        }
        int m = (l + r) >> 1;
        upd(id << 1, l, m, u, v, val);
        upd(id << 1 | 1, m + 1, r, u, v, val);
        t[id] = min(t[id << 1], t[id << 1 | 1]);
    }
    void upd(int l, int r, int val) {
        upd(1, 1, n, l, r, val);
    }
    int get(int id, int l, int r, int u, int v) {
        if (l > v or r < u) return INF;
        if (l >= u and r <= v) return t[id];
        if (lz[id]) {
            mini(t[id << 1], lz[id]);
            mini(t[id << 1 | 1], lz[id]);
            mini(lz[id << 1], lz[id]);
            mini(lz[id << 1 | 1], lz[id]);
            lz[id] = 0;
        }
        int m = (l + r) >> 1;
        return min(get(id<<1,l,m,u,v), get(id<<1|1,m+1,r,u,v));
    }
    int get(int l, int r){
        return get(1,1,n,l,r);
    }

};

void main_code() {
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        cin >> l[i] >> r[i];
    }
    if (n <= 5000) {
        SUB1::sol();
        return ;
    }

    vector<int> val;
    FOR(i, 1, n) {
        val.push_back(l[i]);
        val.push_back(r[i]);
    }
    unq(val);
    FOR(i, 1, n) {
        l[i] = lower_bound(all(val), l[i]) - val.begin() + 1;
        r[i] = lower_bound(all(val), r[i]) - val.begin() + 1;
    }
    segment_tree st(sz(val));
    FOD(i, n, 1) {
        p[i] = min(n + 1, st.get(l[i], r[i]));
        st.upd(l[i], r[i], i);
    }
    int q; cin >> q;

    while (q--) {
        int l, r;
        cin >> l >> r;
        int ans = 1, mi = p[l];
        for(int i = l + 1; i <= n; ++i) {
            if (mi <= i) {
                ++ans;
                mi = p[i];
                continue ;
            }
            mi = min(mi, p[i]);
        }
        cout << ans << nl;
    }
}


/*     Let the river flows naturally     */

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 20 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 50