Submission #397698

#	Time	Username	Problem	Language	Result	Execution time	Memory
397698		ChrisT	Group Photo (JOI21_ho_t3)	C++17	100 / 100	454 ms	98692 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int MN = 5e3 + 5;
int dp[MN], f[MN][MN], a[MN], stopAt[MN];
int main () {
	int n; scanf ("%d",&n);
	for (int i = 1; i <= n; i++) scanf ("%d",&a[i]);
	for (int i = 1; i <= n; i++) {
		for (int j = i+1; j <= n; j++) {
			if (a[i] < a[j]) {
				f[1][a[j]]++; f[a[i]+1][a[j]]--;
			} else {
				f[a[j]+1][a[i]]++; f[a[i]+1][a[i]]--;
			}
		}
	}
	for (int i = 1; i <= n; i++) 
		for (int j = 1; j <= n; j++) 
			f[i][j] += f[i-1][j] + f[i][j-1] - f[i-1][j-1];
	for (int i = 1; i <= n; i++) {
		dp[i] = 1e9;
		for (int j = i; j >= 1; j--) dp[i] = min(dp[i],dp[j-1]+f[j][i]);
	}
	printf ("%d\n",dp[n]);
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:6:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |  int n; scanf ("%d",&n);
      |         ~~~~~~^~~~~~~~~
Main.cpp:7:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 |  for (int i = 1; i <= n; i++) scanf ("%d",&a[i]);
      |                               ~~~~~~^~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 20 / 20
• Subtask 5: 36 / 36