Submission #833887

#	Time	Username	Problem	Language	Result	Execution time	Memory
833887		rainboy	Arcade (NOI20_arcade)	C11	100 / 100	305 ms	14516 KiB

Arcade

#include <stdio.h>

#define N	500000

int max(int a, int b) { return a > b ? a : b; }

unsigned int X = 12345;

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

int xx[N], yy[N];

int compare_y(int i, int j) {
	return yy[i] == yy[j] ? 0 : (yy[i] < yy[j] ? -1 : 1);
}

int compare_xy(int i, int j) {
	return xx[i] != xx[j] ? (xx[i] > xx[j] ? -1 : 1) : (yy[i] == yy[j] ? 0 : (yy[i] > yy[j] ? -1 : 1));
}

int (*compare)(int, int);

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) {
			int c = compare(ii[j], i_);

			if (c == 0)
				j++;
			else if (c < 0) {
				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, int x) {
	while (i < n) {
		ft[i] = max(ft[i], x);
		i |= i + 1;
	}
}

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

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

int main() {
	static int ii[N];
	int n, h, i, x, y;

	scanf("%*d%d", &n);
	for (i = 0; i < n; i++)
		scanf("%d", &xx[i]);
	for (i = 0; i < n; i++)
		scanf("%d", &yy[i]);
	for (i = 0; i < n; i++) {
		x = xx[i] + yy[i], y = xx[i] - yy[i];
		xx[i] = x, yy[i] = y;
	}
	for (i = 0; i < n; i++)
		ii[i] = i;
	compare = compare_y, sort(ii, 0, n);
	for (h = 0, y = 0; h < n; h++)
		yy[ii[h]] = h + 1 == n || yy[ii[h + 1]] != yy[ii[h]] ? y++ : y;
	compare = compare_xy, sort(ii, 0, n);
	for (h = 0; h < n; h++) {
		i = ii[h];
		update(yy[i], n, query(yy[i] - 1) + 1);
	}
	printf("%d\n", query(n - 1));
	return 0;
}

Compilation message (stderr)

Arcade.c: In function 'main':
Arcade.c:70:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |  scanf("%*d%d", &n);
      |  ^~~~~~~~~~~~~~~~~~
Arcade.c:72:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |   scanf("%d", &xx[i]);
      |   ^~~~~~~~~~~~~~~~~~~
Arcade.c:74:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |   scanf("%d", &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 14 / 14
• Subtask 6: 20 / 20
• Subtask 7: 15 / 15