dp[i][0] 表示之前不选的最大值，dp[i][1]表示选这个的最大值，dp[i][2]表示现在以后不选的最大值
#include <bits/stdc++.h> using namespace std; typedef long long ll; const int maxn = 3e5+10; ll a[maxn], dp[maxn][5]; int n,x; ll ans; int main() { scanf("%d%d",&n,&x); for (int i = 1; i <= n; i++) scanf("%lld", &a[i]); for (int i = 1; i <= n; i++) { dp[i][0] = max(dp[i - 1][0] + a[i], a[i]); dp[i][1] = max(dp[i - 1][1] + a[i] * x, max(dp[i - 1][0]+a[i]*x,a[i]*x)); dp[i][2] = max(dp[i - 1][2] + a[i],max(dp[i - 1][1] + a[i], a[i])); if(ans<max( dp[i][0],max(dp[i][1],dp[i][2]))) { ans=max(dp[i][0],max(dp[i][1],dp[i][2])); } } printf("%lld\n", ans); return 0; }
文章来源: https://blog.csdn.net/wzazzy/article/details/89679953