Submission #61962

#	Time	Username	Problem	Language	Result	Execution time	Memory
61962		qkxwsm	Election (BOI18_election)	C++17	100 / 100	2037 ms	39420 KiB

election

/*
PROG: source
LANG: C++11
    _____
  .'     '.
 /  0   0  \
|     ^     |
|  \     /  |
 \  '---'  /
  '._____.'
 */
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
    int operator()(int x) const
	{
		x ^= (x >> 20) ^ (x >> 12);
    	return x ^ (x >> 7) ^ (x >> 4);
	}
	int operator()(long long x) const
	{
		return x ^ (x >> 32);
	}
};

template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using hashtable = gp_hash_table<T, T, chash>;

template<class T>
void readi(T &x)
{
	T input = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
	{
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		input = input * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		input = -input;
	}
	x = input;
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int aout[20];
	int ilen = 0;
	while(output)
	{
		aout[ilen] = ((output % 10));
		output /= 10;
		ilen++;
	}
	for (int i = ilen - 1; i >= 0; i--)
	{
		putchar(aout[i] + '0');
	}
	return;
}
template<class T>
void ckmin(T &a, T b)
{
	a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
	a = max(a, b);
}
template<class T>
T normalize(T x, T mod = 1000000007)
{
	return (((x % mod) + mod) % mod);
}
long long randomizell(long long mod)
{
	return ((1ll << 45) * rand() + (1ll << 30) * rand() + (1ll << 15) * rand() + rand()) % mod;
}
int randomize(int mod)
{
	return ((1ll << 15) * rand() + rand()) % mod;
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 500013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;

int N, Q;
int arr[MAXN];
vector<pii> quer[MAXN];
bool bad[MAXN];
vector<int> pos;
int ans[MAXN];
int inc;
int seg[4 * MAXN], lazy[4 * MAXN];

void push(int w, int L, int R)
{
    seg[w] += lazy[w];
    if (L != R)
    {
        lazy[2 * w] += lazy[w];
        lazy[2 * w + 1] += lazy[w];
    }
    lazy[w] = 0;
    return;
}
void update(int w, int L, int R, int a, int b, int v)
{
    push(w, L, R);
    if (b < L || R < a)
    {
        return;
    }
    if (a <= L && R <= b)
    {
        lazy[w] += v;
        push(w, L, R);
        return;
    }
    int mid = (L + R) / 2;
    update(2 * w, L, mid, a, b, v);
    update(2 * w + 1, mid + 1, R, a, b, v);
    seg[w] = min(seg[2 * w], seg[2 * w + 1]);
}
int query(int w, int L, int R, int a, int b)
{
    push(w, L, R);
    if (b < L || R < a)
    {
        return INF;
    }
    if (a <= L && R <= b)
    {
        return seg[w];
    }
    int mid = (L + R) / 2;
    return min(query(2 * w, L, mid, a, b), query(2 * w + 1, mid + 1, R, a, b));
}

int32_t main()
{
	ios_base::sync_with_stdio(0);
	srand(time(0));
	//	cout << fixed << setprecision(10);
	//	cerr << fixed << setprecision(10);
	if (fopen("input.in", "r"))
	{
		freopen ("input.in", "r", stdin);
		freopen ("output.out", "w", stdout);
	}
    cin >> N;
    string temps;
    cin >> temps;
    for (int i = 0; i < N; i++)
    {
        if (temps[i] == 'C')
        {
            arr[i] = 1;
        }
        else
        {
            arr[i] = -1;
        }
    }
    for (int i = 0; i < N; i++)
    {
        update(1, 0, N, 0, i, arr[i]);
    }
    cin >> Q;
    for (int i = 0; i < Q; i++)
    {
        int l, r;
        cin >> l >> r;
        l--; r--;
        quer[l].PB(MP(r, i));
    }
    pos.PB(N);
    for (int i = N - 1; i >= 0; i--)
    {
        if (arr[i] == 1)
        {
            if (!pos.empty())
            {
                int idx = pos.back();
                pos.pop_back();
                update(1, 0, N, 0, idx, -1);
            }
        }
        else
        {
            pos.PB(i);
            update(1, 0, N, 0, i, 1);
        }
        //now answer all queries
        for (pii p : quer[i])
        {
            // cerr << "qid " << p.se << endl;
            // for (int x : pos)
            // {
            //     cerr << x << ' ';
            // }
            // cerr << endl;
            int qid = p.se, r = p.fi;
            ans[qid] += pos.size();
            // debug(r);
            int lo = 0, hi = pos.size();
            while(hi > lo)
            {
                // cerr << lo << ' ' << hi << endl;
                int mid = (hi + lo + 1) / 2;
                if (pos[mid - 1] <= r)
                {
                    hi = mid - 1;
                }
                else
                {
                    lo = mid;
                }
            }
            // cerr << "lo = " << lo << endl;
            ans[qid] -= lo;
            ans[qid] -= (query(1, 0, N, i, r + 1) - query(1, 0, N, r + 1, r + 1));
        }
    }
    for (int i = 0; i < Q; i++)
    {
        cout << ans[i] << '\n';
    }
	//	cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}

Compilation message (stderr)

election.cpp: In function 'int32_t main()':
election.cpp:204:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("input.in", "r", stdin);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:205:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("output.out", "w", stdout);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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