cf 710E dp

Posted 2020-08-14 a_clown_cz

题目链接： http://codeforces.com/problemset/problem/710/E

题意：要输入n个字符‘a‘,有两种操作，一种是输入或删除一个‘a‘,耗时x；另一种是把当前的整个文本复制粘贴，耗时y。求最少时间。

思路：dp 具体看代码=.=

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
#define ll long long

const int N=1e7+5;
ll dp[N];

ll minn(ll a,ll b){return a<b?a:b;}

int main()
{
    ll n,x,y;
    while(cin>>n>>x>>y)
    {
        dp[1]=x;
        for(int i=2; i<=n; i++)
        {
            if(i%2==0) dp[i]=minn(dp[i-1]+x,dp[i/2]+y);
            else dp[i]=minn(dp[i-1]+x,minn(dp[i/2]+x+y,dp[i/2+1]+x+y));
        }
        cout<<dp[n]<<endl;
    }
    return 0;
}