Submission #1119631

#	Time	Username	Problem	Language	Result	Execution time	Memory
1119631		lmToT27	Election (BOI18_election)	C++17	100 / 100	553 ms	43064 KiB

election

#include <bits/stdc++.h>
#define all(dataStructure) dataStructure.begin(),dataStructure.end()

using namespace std;

typedef long long ll;

const int MAX = 5e5 + 3;
const ll MOD[] = {1000000007, 998244353};

int n;
string st;

struct node_t {
        int maxPre, maxSuf, sum, ans;

        node_t(int a = 0, int b = 0, int c = 0, int d = 0) {
                maxPre = a;
                maxSuf = b;
                sum = c;
                ans = d;
        }
} node[MAX << 2];

node_t combine(const node_t &L, const node_t &R) {
        node_t res;
        res.maxPre = max(L.maxPre, L.sum + R.maxPre);
        res.maxSuf = max(R.maxSuf, R.sum + L.maxSuf);
        res.sum = L.sum + R.sum;
        res.ans = L.maxPre + R.maxSuf;
        res.ans = max(res.ans, L.ans + R.sum);
        res.ans = max(res.ans, R.ans + L.sum);
        return res;
}

void build(int id = 1, int l = 1, int r = n) {
        if (l == r) {
                if (st[l - 1] == 'C') node[id] = node_t(0, 0, -1, 0);
                else node[id] = node_t(1, 1, 1, 1);
        } else {
                int mid = (l + r) / 2;
                build(id << 1, l, mid);
                build(id << 1 | 1, mid + 1, r);
                node[id] = combine(node[id << 1], node[id << 1 | 1]);
        }
}

node_t query(int u, int v, int id = 1, int l = 1, int r = n) {
        if (v < l || r < u) return node_t();
        if (u <= l && r <= v) return node[id];
        int mid = (l + r) / 2;
        return combine(query(u, v, id << 1, l, mid), query(u, v, id << 1 | 1, mid + 1, r));
}

void Solve() {
        cin >> n >> st;
        build();

        int q;
        cin >> q;
        
        while (q--) {
                int l, r;
                cin >> l >> r;
                cout << query(l, r).ans << '\n';
        }
}

int32_t main() {
        std::ios_base::sync_with_stdio(0);
        std::cin.tie(0); std::cout.tie(0);

        #define TASK ""
        if (fopen(TASK".INP", "r")) {
                freopen(TASK".INP", "r", stdin);
                freopen(TASK".OUT", "w", stdout);
        }

        if (fopen("TASK.INP", "r")) {
                freopen("TASK.INP", "r", stdin);
                freopen("TASK.OUT", "w", stdout);
        }

        /* int TEST = 1; cin >> TEST; while (TEST--) */ Solve();

        cerr << "\nTime elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << "s\n";
        return 0;
}

Compilation message (stderr)

election.cpp: In function 'int32_t main()':
election.cpp:75:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |                 freopen(TASK".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:76:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |                 freopen(TASK".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:80:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |                 freopen("TASK.INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:81:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |                 freopen("TASK.OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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