Submission #156463

#	Time	Username	Problem	Language	Result	Execution time	Memory
156463		wilwxk	Watching (JOI13_watching)	C++14	100 / 100	181 ms	8692 KiB

watching

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

const int MAXN=2e3+3;
int v[MAXN], chega[MAXN][2];
int dp[MAXN][MAXN];
int n, x, y;

bool testa(int k) {
	int p=1, p2=1;
	for(int i=1; i<=n; i++) {
		while(p<=n&&v[p]-v[i]<=k-1) p++;
		while(p2<=n&&v[p2]-v[i]<=2*k-1) p2++;
		chega[i][0]=p;
		chega[i][1]=p2;
	}
	chega[0][0]=chega[0][1]=1;
	chega[n+1][0]=chega[n+1][1]=n+1;
	for(int i=0; i<=x; i++) {
		for(int j=0; j<=y; j++) {
			dp[i][j]=1;
			if(i!=0) dp[i][j]=max(dp[i][j], chega[dp[i-1][j]][0]);
			if(j!=0) dp[i][j]=max(dp[i][j], chega[dp[i][j-1]][1]);
			// printf("%d %d >> %d\n", i, j, dp[i][j]);
		}
	}
	return dp[x][y]>n;
}

int main() {
	scanf("%d %d %d", &n, &x, &y);

	if(x+y>=n) {
		printf("1\n");
		return 0;
	}
	for(int i=1; i<=n; i++) scanf("%d", &v[i]);
	sort(v+1, v+1+n);
	for(int i=1; i<=n; i++) {

	}


	// testa(4);
	int respf=0;
	for(int i=1e9; i>0; i/=2) while(!testa(respf+i)) respf+=i;

	printf("%d\n", respf+1);
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &n, &x, &y);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:37:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1; i<=n; i++) scanf("%d", &v[i]);
                          ~~~~~^~~~~~~~~~~~~

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50