Submission #553645

#	Time	Username	Problem	Language	Result	Execution time	Memory
553645		QwertyPi	Watching (JOI13_watching)	C++14	50 / 100	1095 ms	15956 KiB

watching

#include <bits/stdc++.h>
#define N 2001
using namespace std;
 
int dp[N][N];
 
int n, p, q;
vector<int> a;
 
bool ok(int w){
	for(int i = 0; i <= n; i++) for(int j = 0; j <= n; j++) dp[i][j] = (1 << 30); dp[0][0] = 0;
	for(int j = 0; j <= n; j++){
		int w1 = 0, w2 = 0;
		for(int i = 1; i <= n; i++){
			while(w2 < n && a[w2] <= a[i - 1] - w * 2) w2++; w1 = max(w1, w2);
			while(w1 < n && a[w1] <= a[i - 1] - w) w1++;
			if(j > 0) dp[i][j] = min(dp[i][j], dp[w2][j - 1]);
			dp[i][j] = min(dp[i][j], dp[w1][j] + 1);
		}
		for(int i = 1; i <= n; i++) dp[i][j + 1] = min(dp[i][j], dp[i][j + 1]);
	}
	return dp[n][q] <= p;
}
 
int main(){
	cin >> n >> p >> q;
	p = min(n, p); q = min(n, q);
	for(int i = 0; i < n; i++){
		int v; cin >> v;
		a.push_back(v);
	}
	sort(a.begin(), a.end());
	int l, r;
	for(l = 0, r = 1e9 + 1; l != r;){
		int m = (l + r) / 2;
		if(ok(m)){
			r = m;
		}else{
			l = m + 1;
		}
	}
	cout << l << endl;
}

Compilation message (stderr)

watching.cpp: In function 'bool ok(int)':
watching.cpp:11:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   11 |  for(int i = 0; i <= n; i++) for(int j = 0; j <= n; j++) dp[i][j] = (1 << 30); dp[0][0] = 0;
      |  ^~~
watching.cpp:11:80: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   11 |  for(int i = 0; i <= n; i++) for(int j = 0; j <= n; j++) dp[i][j] = (1 << 30); dp[0][0] = 0;
      |                                                                                ^~
watching.cpp:15:4: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
   15 |    while(w2 < n && a[w2] <= a[i - 1] - w * 2) w2++; w1 = max(w1, w2);
      |    ^~~~~
watching.cpp:15:53: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
   15 |    while(w2 < n && a[w2] <= a[i - 1] - w * 2) w2++; w1 = max(w1, w2);
      |                                                     ^~

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50