Submission #28838

#	Time	Username	Problem	Language	Result	Execution time	Memory
28838		ulna	K blocks (IZhO14_blocks)	C++11	0 / 100	323 ms	10228 KiB

blocks

#include <bits/stdc++.h>
using namespace std;

// why am I so weak

int n, k;
int a[100055];

int dp[2][100055];

#define MAX_LOG 17

int lg[100055];
int dat[MAX_LOG][100055];

inline int rmq(int x, int y) {
	int dist = y - x + 1;
	int level = lg[dist];
	return max(dat[level][x], dat[level][y - (1 << level) + 1]);
}
inline int f(int i, int j) {
	return dp[0][i] + rmq(i + 1, j);
}
void solve(int l, int r, int optl, int optr) {
	if (l > r) return;

	int mid = (l + r) >> 1;
	int opt = optl;

	for (int i = optl; i <= min(optr, mid - 1); i++) {
		if (f(i, mid) < f(opt, mid)) {
			opt = i;
		}
	}

	dp[1][mid] = f(opt, mid);

	solve(l, mid - 1, optl, opt);
	solve(mid + 1, r, opt, optr);
}	
int main() {
	// dp[i][j] = min(dp[k][j - 1] + max(k + 1.. i))
	// max(k + 1.. i) is non-increasing
	// dp[k][j - 1] is non-decreasing
	
	scanf("%d %d", &n, &k);

	for (int i = 1; i <= n; i++) {
		scanf("%d", &a[i]);
		dat[0][i] = a[i];
	}

	for (int i = 2; i <= n; i++) {
		lg[i] = lg[i / 2] + 1;
	}

	for (int i = 0; i + 1 < MAX_LOG; i++) {
		for (int j = 1; j + (1 << i) <= n; j++) {
			dat[i + 1][j] = max(dat[i][j], dat[i][j + (1 << i)]);
		}
	}

	memset(dp, 63, sizeof(dp));

	dp[1][0] = 0;

	while (k--) {
		swap(dp[0], dp[1]);
		memset(dp[1], 63, sizeof(dp[1]));

		solve(1, n, 0, n);
	}

	printf("%d\n", dp[1][n]);
	
	return 0;
}

Compilation message (stderr)

blocks.cpp: In function 'int main()':
blocks.cpp:46:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &k);
                        ^
blocks.cpp:49:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
                     ^

• Subtask 1: 0 / 14
• Subtask 2: 0 / 18
• Subtask 3: 0 / 21
• Subtask 4: 0 / 47