dp 俩种状态。dp[i][0] 表示不取,dp[i][1]表示取
如果i取 那么dp[i][1] = dp[i - 1][0] + s[i]
如果i 不取 dp[i][0] = Max(dp[i -1][0],dp[i - 1][1]
注意数据范围。
#include <cstdio> #include <iostream> #include <cstring> #include <algorithm> using namespace std; typedef __int64 ll; int const MAXN = 100010; ll dp[MAXN][2],s[MAXN]; inline ll Max(ll a,ll b){ return a>b?a:b; } int main(){ int n; scanf("%d",&n); memset(s,0,sizeof(s)); for(int i = 1;i <= n;i++){ int x; scanf("%d",&x); s[x] += x; } memset(dp,0,sizeof(dp)); for(int i = 1;i <= 100001;i++){ dp[i][0] = Max(dp[i - 1][1],dp[i - 1][0]); dp[i][1] = dp[i - 1][0] + s[i]; } printf("%I64d\n",dp[100001][0]); return 0; }