Submission #762764

#	Time	Username	Problem	Language	Result	Execution time	Memory
762764		rainboy	Loop Town (CCO21_day2problem3)	C11	0 / 25	3 ms	468 KiB

Main

#include <stdio.h>

#define N	1000000

long long min(long long a, long long b) { return a < b ? a : b; }

unsigned int X = 12345;

int rand_() {
	return (X *= 3) >> 1;
}

int *zz;

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;

		while (j < k)
			if (zz[ii[j]] == zz[i_])
				j++;
			else if (zz[ii[j]] < zz[i_]) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		sort(ii, l, i);
		l = k;
	}
}

int ft[N];

void update(int i, int n) {
	while (i < n) {
		ft[i]++;
		i |= i + 1;
	}
}

int query(int i) {
	int x = 0;

	while (i >= 0) {
		x += ft[i];
		i &= i + 1, i--;
	}
	return x;
}

int main() {
	static int xx[N], yy[N], ii[N], pp[N];
	int n, l, i;
	long long k, ans;

	scanf("%d%d", &n, &l);
	for (i = 0; i < n; i++)
		scanf("%d%d", &xx[i], &yy[i]);
	for (i = 0; i < n; i++)
		ii[i] = i;
	zz = xx, sort(ii, 0, n);
	for (i = 0; i < n; i++)
		xx[ii[i]] = i;
	zz = yy, sort(ii, 0, n);
	for (i = 0; i < n; i++)
		yy[ii[i]] = i;
	for (i = 0; i < n; i++)
		pp[xx[i]] = yy[i];
	k = 0;
	for (i = 0; i < n; i++) {
		k += query(n - 1 - pp[i]);
		update(n - 1 - pp[i], n);
	}
	ans = k;
	for (i = 0; i < n; i++)
		ans = min(ans, k += n - 1 - pp[i] * 2);
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

Main.c: In function 'main':
Main.c:58:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |  scanf("%d%d", &n, &l);
      |  ^~~~~~~~~~~~~~~~~~~~~
Main.c:60:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |   scanf("%d%d", &xx[i], &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 6
• Subtask 3: 0 / 7