1564 区间的价值

分治

#include<stdio.h>
#include<math.h>
#include<cstring>
#include<stack>
#include<iostream>
#include<algorithm>
#include<queue>
#define MAXSIZE 100005
#define LL long long

using namespace std;
const LL INF = 1e19;

LL a[MAXSIZE],dp[MAXSIZE];

void Solve(int l,int r)
{
    if(l > r)
        return;
    LL maxn=0,minn=INF;
    int pmax,pmin,maxnlen,minnlen;
    for(int i=l;i<=r;i++)
    {
        if(maxn < a[i])
        {
            maxn = a[i];
            pmax = i;
        }

        if(minn > a[i])
        {
            minn = a[i];
            pmin = i;
        }
    }

    minnlen = fabs(pmax-pmin)+1;
    maxnlen = r-l+1;
    for(int i=minnlen;i<=maxnlen;i++)
        dp[i] = max(dp[i],minn*maxn);
    Solve(l,pmin-1);
    Solve(pmin+1,r);
}

int main()
{
    memset(dp,0,sizeof(dp));
    int n;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
        scanf("%lld",&a[i]);
    Solve(1,n);
    for(int i=1;i<=n;i++)
        printf("%lld
",dp[i]);
    return 0;
}