Submission #22976

#	Time	Username	Problem	Language	Result	Execution time	Memory
22976		Bruteforceman	Watching (JOI13_watching)	C++11	100 / 100	296 ms	21332 KiB

watching

#include <bits/stdc++.h>
using namespace std;
int N, P, Q;
int a[2222];
int big[2222];
int tiny[2222];

int search(int b, int e, int val) {
    if(b == e) {
        return b;
    }
    int m = (b + e) >> 1;
    if(val < a[m]) return search(b, m, val);
    else return search(m + 1, e, val);
}

const int inf = 1e8;

int dp[2222][2222];

bool good(int w) {
    for(int i = 1; i <= N; i++) {
        tiny[i] = search(1, N, a[i] - w) - 1;
        big[i] = search(1, N, a[i] - w - w) - 1;
    }
    for(int i = 1; i <= N; i++) {
        for(int j = 0; j <= P; j++) {
            dp[i][j] = inf;
            if(j) dp[i][j] = min(dp[i][j], dp[tiny[i]][j - 1]);
            dp[i][j] = min(dp[i][j], dp[big[i]][j] + 1);
        }
    }
    return (dp[N][P] <= Q);
} 

int find(int b, int e) {
    if(b == e) {
        return b;
    }
    int m = (b + e) >> 1;
    if(good(m)) return find(b, m);
    else return find(m + 1, e);
}

int main() {
    scanf("%d %d %d", &N, &P, &Q);
    for(int i = 1; i <= N; i++) {
        scanf("%d", &a[i]);
    }
    sort(a + 1, a + N + 1);
    if(N <= P || N <= Q) {
        printf("%d\n", 1);
        exit(0);
    }
    printf("%d\n", find(1, 1000000000));
    return 0;
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:46:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &N, &P, &Q);
                                  ^
watching.cpp:48:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &a[i]);
                           ^

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