P1040 [NOIP2003 提高组] 加分二叉树

原题链接

题解

计算分数是搜索
存储前缀注意细节

code

#include<bits/stdc++.h>
using namespace std;

#define ll long long

ll sco[35][35]={0};
string pre[35][35];
ll a[35]={0};
queue<ll> q;

inline void read(ll &x) {
    x = 0;
    ll flag = 1;
    char c = getchar();
    while(c < '0' || c > '9'){
        if(c == '-')flag = -1;
        c = getchar();
    }
    while(c >= '0' && c <= '9') {
        x = (x << 3) + (x << 1) + (c ^ 48);
        c = getchar();
    }
    x *= flag;
}

inline void write(ll x)
{
    if(x < 0){
        putchar('-');
        x = -x;
    }
    if(x > 9)
        write(x / 10);
    putchar(x % 10 + '0');
}

string turn(ll x)
{
    string s;
    while(x)
    {
        char d='0'+x%10;
        s=d+s;
        x/=10;
    }
    return s;
}

ll ss(ll l,ll r)
{
    if(r<l)
    {
        sco[l][r]=1;
        pre[l][r]="";
        return 1;
    }
    if(l==r)
    {
        sco[l][r]=a[l];
        pre[l][r]=turn(l)+' ';//细节
        return a[l];
    }
    if(sco[l][r]) return sco[l][r];
    ll val=0,index;
    for(ll i=l;i<=r;i++)
    {
        ll next=ss(l,i-1)*ss(i+1,r)+a[i];
        if(next>val)
        {
            val=next;
            index=i;
            string add=turn(i);
            pre[l][r]=add+' '+pre[l][i-1]+pre[i+1][r];//细节每个数字后跟一个空格
        }
    }
    sco[l][r]=val;

    return sco[l][r];
}
int main()
{
    ll n;
    read(n);
    for(ll i=1;i<=n;i++) read(a[i]);

    ll index,val=0;
    write(ss(1,n));
    putchar('\n');
    cout<<pre[1][n]<<endl;
    return 0;
}