Submission #74578

#	Time	Username	Problem	Language	Result	Execution time	Memory
74578		Good	Election (BOI18_election)	C++11	0 / 100	16 ms	504 KiB

election

#include <bits/stdc++.h>

#define ff first
#define ss second
#define Maxn 100009
#define ll long long
#define pb push_back
#define Inf 1000000009
#define ppb() pop_back()
#define pii pair <int , int>
#define mid(x, y) (x + y) / 2
#define all(x) x.begin(),x.end()
#define llInf 1000000000000000009
using namespace std;

int n, q, S;
char a[Maxn];
int prt[Maxn];
int ans[Maxn];
int A[Maxn][2];
int T[Maxn * 4][2];

vector <int> v;
vector <pair <pii, int> > Q;

void upd (int x, int l, int r, int v, bool type, int add) {
	if (l == r) {
		T[v][type] += add;
		return;
	}
	
	if (x <= mid (l, r))
		upd (x, l, mid (l, r), v * 2, type, add);
	
	else
		upd (x, mid (l, r) + 1, r, v * 2 + 1, type, add);
	
	T[v][type] = T[v * 2][type] + T[v * 2 + 1][type];		
}

int get (int x, int y, int l, int r, int v, bool type) {
	if (l > y or r < x)
		return 0;
	
	if (l >= x and r <= y)
		return T[v][type];	
	
	return get (x, y, l, mid (l, r), v * 2, type) + get (x, y, mid (l, r) + 1, r, v * 2 + 1, type);	
}

bool cmp (pair <pii, int> x, pair <pii, int> y) {
	if (x.ff.ff / S == y.ff.ff / S)
		return (x.ff.ss > y.ff.ss);
		
	return (x.ff.ff / S < y.ff.ff / S);	
}

int main () {
	//freopen ("file.in", "r", stdin);
	//freopen ("file.out", "w", stdout);
	
 	//srand ((unsigned) time ( NULL ));
	//int randomNumber = rand() % 10 + 1;

	scanf ("%d %s", &n, a);
	S = sqrt (n);
	
	for (int i = 1; i <= n; i++) {
		prt[i] = prt[i - 1];
		
		if (a[i - 1] == 'C')
			v.pb (i);
		
		else {
			prt[i] ++;
			
			if (v.size())
				A[i][0] = v.back(), v.ppb();				
		}		
	}
	
	v.clear();
	for (int i = n; i >= 1; i--) {
		if (a[i - 1] == 'C')
			v.pb (i);
		
		else
			if (v.size())
				A[i][1] = v.back(), v.ppb ();
	}
				
	scanf ("%d", &q);

	for (int i = 1; i <= q; i++) {
		int l, r;
		scanf ("%d%d", &l, &r);
		
		Q.pb ({{l, r}, i});
	}
	
	sort (all (Q), cmp);
	
	int l = 1, r = 1;
		
	for (auto i: Q) {
		while (l > i.ff.ff) {
			if (A[l - 1][0])
				upd (A[l - 1][0], 1, n, 1, 0, 1);
			if (A[l - 1][1])
				upd (A[l - 1][1], 1, n, 1, 1, 1);
			
			l --;
		}
		
		while (l < i.ff.ff) {
			if (A[l][0])
				upd (A[l][0], 1, n, 1, 0, -1);
				
			if (A[l][1])
				upd (A[l][1], 1, n, 1, 1, -1);	
			
			l ++;
		}
		
		while (r <= i.ff.ss) {
			if (A[r][0])
				upd (A[r][0], 1, n, 1, 0, 1);
			if (A[r][1])
				upd (A[r][1], 1, n, 1, 1, 1);
			
			r ++;		
		}
		
		while (r > i.ff.ss + 1) {
			if (A[r - 1][0])
				upd (A[r - 1][0], 1, n, 1, 0, -1);
			if (A[r - 1][1])
				upd (A[r - 1][1], 1, n, 1, 1, -1);
			
			r--;		
		}
							
		ans[i.ss] = prt[i.ff.ss] - prt[i.ff.ff - 1] - min (get (i.ff.ff, i.ff.ss, 1, n, 1, 0), get (i.ff.ff, i.ff.ss, 1, n, 1, 1));	
	}
	
	for (int i = 1; i <= q; i++)
		printf ("%d\n", ans[i]);
		
	return 0;
}

Compilation message (stderr)

election.cpp: In function 'int main()':
election.cpp:65:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d %s", &n, a);
  ~~~~~~^~~~~~~~~~~~~~~~
election.cpp:92:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d", &q);
  ~~~~~~^~~~~~~~~~
election.cpp:96:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf ("%d%d", &l, &r);
   ~~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 28
• Subtask 2: 0 / 54
• Subtask 3: 0 / 18