제출 #787227

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
787227		MilosMilutinovic	송신탑 (IOI22_towers)	C++17	100 / 100	1735 ms	39416 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
const int L = 22;
int n, a[N], pl[N], pr[N], ord[N], go_l[N], go_r[N];
bool cmp(int i, int j) { return a[i] < a[j]; }
int mx[N][L], logs[N];
int qmx(int l, int r) {
    if (l > r) return (int) -1e9;
    int k = logs[r - l + 1];
    return max(mx[l][k], mx[r - (1 << k) + 1][k]);
}
void buildST() {
    for (int i = 1; i <= n; i++) mx[i][0] = a[i];
    for (int i = 2; i <= n; i++) logs[i] = logs[i >> 1] + 1;
    for (int j = 1; j < L; j++)
        for (int i = 1; i + (1 << j) <= n + 1; i++)
            mx[i][j] = max(mx[i][j - 1], mx[i + (1 << (j - 1))][j - 1]);
}
const int M = N * L;
int tsz, ls[M], rs[M], sum[M];
void modify(int& v, int p, int tl, int tr, int i, int x) {
    v = ++tsz;
    ls[v] = ls[p];
    rs[v] = rs[p];
    sum[v] = sum[p] + x;
    if (tl == tr) {
        return;
    }
    int mid = tl + tr >> 1;
    if (i <= mid) {
        modify(ls[v], ls[p], tl, mid, i, x);
    } else {
        modify(rs[v], rs[p], mid + 1, tr, i, x);
    }
}
int query(int v, int tl, int tr, int ql, int qr) {
    if (tl > tr || tl > qr || tr < ql) {
        return 0;
    }
    if (ql <= tl && tr <= qr) {
        return sum[v];
    }
    int mid = tl + tr >> 1;
    return query(ls[v], tl, mid, ql, qr) + query(rs[v], mid + 1, tr, ql, qr);
}
int find_first(int v, int tl, int tr, int p) {
    if (tr < p || !sum[v]) {
        return n + 1;
    }
    if (tl == tr) {
        return sum[v] > 0 ? tl : n + 1;
    }
    int mid = tl + tr >> 1;
    int ans_l = find_first(ls[v], tl, mid, p);
    if (ans_l == n + 1)
        return find_first(rs[v], mid + 1, tr, p);
    else
        return ans_l;
}
int find_last(int v, int tl, int tr, int p) {
    if (tl > p || !sum[v]) {
        return 0;
    }
    if (tl == tr) {
        return sum[v] > 0 ? tl : 0;
    }
    int mid = tl + tr >> 1;
    int ans_r = find_last(ls[v], mid + 1, tr, p);
    if (ans_r == 0)
        return find_last(ls[v], tl, mid, p);
    else
        return ans_r;
}
struct node {
    int mn, mx, l_diff, r_diff;
};
node comb(node nl, node nr) {
    node res;
    res.mn = min(nl.mn, nr.mn);
    res.mx = max(nl.mx, nr.mx);
    res.l_diff = max({nl.l_diff, nr.l_diff, nr.mx - nl.mn});
    res.r_diff = max({nl.r_diff, nr.r_diff, nl.mx - nr.mn});
    return res;
}
namespace segtree {
    node st[8 * N];
    void build(int v, int tl, int tr) {
        if (tl == tr) {
            st[v].mn = a[tl];
            st[v].mx = a[tl];
            st[v].l_diff = 0;
            st[v].r_diff = 0;
            return;
        }
        int mid = tl + tr >> 1;
        build(v * 2, tl, mid);
        build(v * 2 + 1, mid + 1, tr);
        st[v] = comb(st[v * 2], st[v * 2 + 1]);
    }
    node query(int v, int tl, int tr, int ql, int qr) {
        if (tl > tr || tl > qr || tr < ql) {
            assert(false);
        }
        if (ql <= tl && tr <= qr) {
            return st[v];
        }
        int mid = tl + tr >> 1;
        if (qr <= mid) {
            return query(v * 2, tl, mid, ql, qr);
        } else if (ql > mid) {
            return query(v * 2 + 1, mid + 1, tr, ql, qr);
        } else {
            return comb(query(v * 2, tl, mid, ql, qr), query(v * 2 + 1, mid + 1, tr, ql, qr));
        }
    }
};
vector<pair<int, int>> qs;
vector<int> roots;
void init(int N, vector<int> H) {
    n = N;
    for (int i = 1; i <= n; i++) {
        a[i] = H[i - 1];
    }
    segtree::build(1, 1, n);
    go_r[1] = 1;
    for (int i = 2; i <= n; i++) {
        go_r[i] = (a[i - 1] < a[i] ? go_r[i - 1] : i);
    }
    go_l[n] = n;
    for (int i = n - 1; i >= 1; i--) {
        go_l[i] = (a[i + 1] < a[i] ? go_l[i + 1] : i);
    }
    vector <int> stk;
    for (int i = 1; i <= n; i++) {
        while (!stk.empty() && a[stk.back()] > a[i]) stk.pop_back();
        pl[i] = (stk.empty() ? -1 : stk.back());
        stk.push_back(i);
    }
    stk.clear();
    for (int i = n; i >= 1; i--) {
        while (!stk.empty() && a[stk.back()] > a[i]) stk.pop_back();
        pr[i] = (stk.empty() ? -1 : stk.back());
        stk.push_back(i);
    }
    buildST();
    for (int i = 1; i <= n; i++) ord[i] = i;
    sort(ord + 1, ord + n + 1, cmp);
    for (int _i = 2; _i <= n; _i++) {
        int i = ord[_i];
        int D = 1.001e9;
        if (pl[i] != -1) D = min(D, qmx(pl[i] + 1, i) - a[i]);
        if (pr[i] != -1) D = min(D, qmx(i, pr[i] - 1) - a[i]);
        qs.emplace_back(D, i);
    }
    sort(qs.begin(), qs.end());
    roots.push_back(0);
    modify(roots.back(), roots.back(), 1, n, ord[1], 1);
    int sz = (int) qs.size();
    for (int i = sz - 1; i >= 0; i--) {
        int prv = (int) roots.back();
        roots.push_back(0);
        modify(roots.back(), prv, 1, n, qs[i].second, 1);
    }
    reverse(roots.begin(), roots.end());
}
int get_pos(int d) {
    int low = 0, high = (int) qs.size() - 1, res = high + 1;
    while (low <= high) {
        int mid = low + high >> 1;
        if (qs[mid].first >= d) {
            res = mid;
            high = mid - 1;
        } else {
            low = mid + 1;
        }
    }
    return res;
}
int find_first_bs(int rt, int p) {
    int low = p, high = n, res = n;
    while (low <= high) {
        int mid = low + high >> 1;
        if (query(rt, 1, n, p, mid) > 0) {
            res = mid;
            high = mid - 1;
        } else {
            low = mid + 1;
        }
    }
    return res;
}
int find_last_bs(int rt, int p) {
    int low = 1, high = p, res = 1;
    while (low <= high) {
        int mid = low + high >> 1;
        if (query(rt, 1, n, mid, p) > 0) {
            res = mid;
            low = mid + 1;
        } else {
            high = mid - 1;
        }
    }
    return res;
}
int max_towers(int L, int R, int D) {
    if (L == R) {
        return 1;
    }
    ++L; ++R;
    int p = get_pos(D);
    int ans = query(roots[p], 1, n, L, R);
    if (ans == 0) {
        int low = L, high = R, pos = R;
        while (low <= high) {
            int mid = low + high >> 1;
            if (segtree::query(1, 1, n, L, mid).l_diff >= D) {
                pos = mid;
                high = mid - 1;
            } else {
                low = mid + 1;
            }
        }
        if (segtree::query(1, 1, n, L, pos).l_diff >= D && segtree::query(1, 1, n, pos, R).r_diff >= D)
            return 2;
        else
            return 1;
    }
    int l = find_first_bs(roots[p], L);
    int r = find_last_bs(roots[p], R);
    if (L < l) {
        int low = L, high = l - 1, pos = l;
        while (low <= high) {
            int mid = low + high >> 1;
            if (qmx(mid, l - 1) >= a[l] + D) {
                pos = mid;
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        if (pos != l && segtree::query(1, 1, n, L, pos).l_diff >= D) {
            ans += 1;
        }
    }
    if (r < R) {
        int low = r + 1, high = R, pos = r;
        while (low <= high) {
            int mid = low + high >> 1;
            if (qmx(r + 1, mid) >= a[r] + D) {
                pos = mid;
                high = mid - 1;
            } else {
                low = mid + 1;
            }
        }
        if (pos != r && segtree::query(1, 1, n, pos, R).r_diff >= D) {
            ans += 1;
        }
    }
//    for (int i = L; i < l; i++) {
//        if (max(a[i], a[l]) <= qmx(i, l) - D) {
//            ans += 1;
//            break;
//        }
//    }
//    for (int i = R; i > r; i--) {
//        if (max(a[r], a[i]) <= qmx(r, i) - D) {
//            ans += 1;
//            break;
//        }
//    }
    return ans;
}

/*
7 3
10 20 60 40 50 30 70
1 5 10
2 2 100
0 6 17


3
1
2
*/

컴파일 시 표준 에러 (stderr) 메시지

towers.cpp: In function 'void modify(int&, int, int, int, int, int)':
towers.cpp:31:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   31 |     int mid = tl + tr >> 1;
      |               ~~~^~~~
towers.cpp: In function 'int query(int, int, int, int, int)':
towers.cpp:45:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   45 |     int mid = tl + tr >> 1;
      |               ~~~^~~~
towers.cpp: In function 'int find_first(int, int, int, int)':
towers.cpp:55:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   55 |     int mid = tl + tr >> 1;
      |               ~~~^~~~
towers.cpp: In function 'int find_last(int, int, int, int)':
towers.cpp:69:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |     int mid = tl + tr >> 1;
      |               ~~~^~~~
towers.cpp: In function 'void segtree::build(int, int, int)':
towers.cpp:97:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   97 |         int mid = tl + tr >> 1;
      |                   ~~~^~~~
towers.cpp: In function 'node segtree::query(int, int, int, int, int)':
towers.cpp:109:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  109 |         int mid = tl + tr >> 1;
      |                   ~~~^~~~
towers.cpp: In function 'int get_pos(int)':
towers.cpp:171:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  171 |         int mid = low + high >> 1;
      |                   ~~~~^~~~~~
towers.cpp: In function 'int find_first_bs(int, int)':
towers.cpp:184:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  184 |         int mid = low + high >> 1;
      |                   ~~~~^~~~~~
towers.cpp: In function 'int find_last_bs(int, int)':
towers.cpp:197:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  197 |         int mid = low + high >> 1;
      |                   ~~~~^~~~~~
towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:217:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  217 |             int mid = low + high >> 1;
      |                       ~~~~^~~~~~
towers.cpp:235:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  235 |             int mid = low + high >> 1;
      |                       ~~~~^~~~~~
towers.cpp:250:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  250 |             int mid = low + high >> 1;
      |                       ~~~~^~~~~~

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• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 14 / 14
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• Subtask 7: 23 / 23