제출 #1287334

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1287334		wedonttalkanymore	Election (BOI18_election)	C++20	100 / 100	403 ms	66732 KiB

election

#include <bits/stdc++.h>
/*
    Phia ben kia dai duong cung chi co
    Bo cat nang niu bien thoi
*/
using namespace std;
using ll = long long;

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 5e5 + 5, inf = 1e18, mod = 1e9 + 7, block = 320, lim = 19;

int n;
char a[N];
int q;

struct ST {
    struct item {
        int L, R, sum, ans;
        item() : L(0), R(0), sum(0), ans(0) {}
    };
    vector <item> st;
    ST (int _n) {
        st.assign(4 * (_n + 1), item());
    }
    item combine(item &A, item &B) {
        item C;
        C.L = max(A.L, A.sum + B.L);
        C.R = max(B.R, A.R + B.sum);
        C.sum = A.sum + B.sum;
        C.ans = max({A.ans + B.sum, A.sum + B.ans, A.L + B.R});
        return C;
    }
    void update(int i, int l, int r, int pos, char val) {
        if (l == r) {
            item tmp;
            if (val == 'C') {
                tmp.L = 0, tmp.R = 0, tmp.sum = -1, tmp.ans = 0;
            } 
            else {
                tmp.L = 1, tmp.R = 1, tmp.sum = 1, tmp.ans = 1;
            }
            st[i] = tmp;
            return;
        }
        int mid = (l + r) / 2;
        if (pos <= mid) update(2 * i, l, mid, pos, val);
        else update(2 * i + 1, mid + 1, r, pos, val);
        st[i] = combine(st[2 * i], st[2 * i + 1]);
    }
    item get(int i, int l, int r, int u, int v) {
        if (u > r || v < l) return item();
        if (u <= l && r <= v) return st[i];
        int mid = (l + r) / 2;
        auto L = get(2 * i, l, mid, u, v);
        auto R = get(2 * i + 1, mid + 1, r, u, v);
        return combine(L, R);
    }
} st(N);

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        st.update(1, 1, n, i, a[i]);
    }
    cin >> q;
    while(q-- > 0) {
        int l, r;
        cin >> l >> r;
        cout << st.get(1, 1, n, l, r).ans << '\n';
    }
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

election.cpp: In function 'int main()':
election.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
election.cpp:69:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 28 / 28
• Subtask 2: 54 / 54
• Subtask 3: 18 / 18