Submission #954102

#	Time	Username	Problem	Language	Result	Execution time	Memory
954102		Beerus13	Index (COCI21_index)	C++14	0 / 110	61 ms	96596 KiB

index

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 2e5 + 5;
const int K = 20;
const int inf = 1e9;

struct node {
    int x, l, r;
    node() { x = l = r = 0; }
    node(int x, int l, int r) : x(x), l(l), r(r) {}
};

int n, q, a[N], nNode, nver, ver[N];
node st[N * K];

node refine(int cur) {
    st[cur].x = st[st[cur].l].x + st[st[cur].r].x;
}

int update(int pos, int val, int old, int l = 1, int r = N - 1) {
    int cur = ++nNode;
    if(l == r) {
        st[cur] = node(st[old].x + val, 0, 0);
        return cur;
    }
    int m = l + r >> 1;
    if(pos <= m) {
        st[cur].l = update(pos, val, st[old].l, l, m);
        st[cur].r = st[old].r;
    }
    else {
        st[cur].l = st[old].l;
        st[cur].r = update(pos, val, st[old].r, m + 1, r);
    }
    refine(cur);
    return cur;
}

int get(int ver, int u, int v, int l = 1, int r = N - 1) {
    if(u > r || v < l) return 0;
    if(u <= l && r <= v) return st[ver].x;
    int m = l + r >> 1;
    return get(st[ver].l, u, v, l, m) + get(st[ver].r, u, v, m + 1, r);
}

void solve() {
    cin >> n >> q;
    for(int i = 1; i <= n; ++i) {
        cin >> a[i];
        ver[i] = update(a[i], 1, ver[i - 1]);
    }
    while(q--) {
        int ql, qr; cin >> ql >> qr;
        int l = 1, r = 2e5, ans;
        while(l <= r) {
            int m = l + r >> 1;
            if(get(ver[qr], m, N - 1) - get(ver[ql - 1], m, N - 1) >= m) ans = m, l = m + 1;
            else r = m - 1;
        }
        cout << ans << '\n';
    }
}

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int test = 1;
    // cin >> test;
    while(test--) solve();
    return 0;
}

Compilation message (stderr)

index.cpp: In function 'node refine(int)':
index.cpp:19:1: warning: no return statement in function returning non-void [-Wreturn-type]
   19 | }
      | ^
index.cpp: In function 'int update(int, int, int, int, int)':
index.cpp:27:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   27 |     int m = l + r >> 1;
      |             ~~^~~
index.cpp: In function 'int get(int, int, int, int, int)':
index.cpp:43:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   43 |     int m = l + r >> 1;
      |             ~~^~~
index.cpp: In function 'void solve()':
index.cpp:57:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   57 |             int m = l + r >> 1;
      |                     ~~^~~
index.cpp:61:24: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   61 |         cout << ans << '\n';
      |                        ^~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 40
• Subtask 3: 0 / 50