Codeforces Round #260 (Div. 1) A. Boredom (简单dp)

题目链接:http://codeforces.com/problemset/problem/455/A

给你n个数,要是其中取一个大小为x的数,那x+1和x-1都不能取了,问你最后取完最大的和是多少。

简单dp,dp[i]表示取i时zui最大和为多少,方程为dp[i] = max(dp[i - 1] , dp[i - 2] + cont[i]*i)。

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef __int64 LL;
 4 const int MAXN = 1e5 + 5;
 5 LL a[MAXN] , cont[MAXN] , dp[MAXN];
 6 int main()
 7 {
 8     int n;
 9     scanf("%d" , &n);
10     for(int i = 1 ; i <= n ; ++i) {
11         scanf("%lld" , a + i);
12         ++cont[a[i]];
13     }
14     dp[1] = cont[1] * 1;
15     for(int i = 2 ; i <= 1e5 ; ++i) {
16         dp[i] = max(dp[i - 1] , dp[i - 2] + cont[i] * i);
17     }
18     printf("%lld\n" , dp[int(1e5)]);
19     return 0;
20 }
时间: 2024-10-24 08:37:20

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