Submission #270366

#	Time	Username	Problem	Language	Result	Execution time	Memory
270366		Hehehe	Palindrome-Free Numbers (BOI13_numbers)	C++14	88.75 / 100	1 ms	512 KiB

numbers

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define dbg(x) cout << #x << '=' << x << '\n';
#define ll long long
#define x first
#define y second
#define pi pair <int, int>
#define vi vector <int>
#define L nod<<1
#define R ((nod<<1)|1)
#define mp make_pair
#define sz(x) (int)((x).size())
const ll mod = 1000000007;
const ll nmax=1000003;
#define int ll
int a, b;
int dp[20][11][11][2];
 
int f(int x){
    memset(dp, 0, sizeof(dp));
    
    if(x <= 9)return x + 1;
    
    int ans = 0;
    vector<int>v;

    string s = to_string(x);
    for(auto it : s)v.push_back(it - '0');
    
    int n = sz(v);
    
    //i == 0
    for(int cur = 1; cur <= 9; cur++){
        if(cur > v[0])break;
        dp[0][10][cur][(cur == v[0])] = 1;
    }
    
    for(int i=1; i<n; i++){
		//dp[i][10][10][0]=1;
        if(i==1){
            for(int next=1; next<=9; next++){
                dp[i][10][next][0]=1;
            }
            for(int xd2=1; xd2<=9; xd2++){
                for(int eq=0; eq<2; eq++){
                    for(int next=0; next<=9; next++){
                        if((eq && next>v[i]) || xd2==10) break;
                        int ctrl=(eq&(next==v[i]));
                        if(next!=xd2) dp[i][xd2][next][ctrl]+=dp[i-1][10][xd2][eq];
                    }
                }
            }
            continue;
        }
        else{
			for(int next=1; next<=9; next++){
                dp[i][10][next][0]=1;
            }
            for(int xd2=1; xd2<=9; xd2++){
                for(int next=0; next<=9; next++){
                    if(next!=xd2) dp[i][xd2][next][0]+=dp[i-1][10][xd2][0];
                }
            }
            for(int xd1=0; xd1<=9; xd1++){
                for(int xd2=0; xd2<=9; xd2++){
                    for(int eq=0; eq<2; eq++){
                        for(int next=0; next<=9; next++){
                            if(eq && next>v[i]) break;
                            int ctrl=(eq&(next==v[i]));
                            if(next!=xd1 && next!=xd2) dp[i][xd2][next][ctrl]+=dp[i-1][xd1][xd2][eq];
                        }
                    }
                }
            }
        }
    }
    //for(int i=0; i<v.size(); i++){
    for(int xd1=0; xd1<=10; xd1++){
            for(int xd2=0; xd2<=10; xd2++){
                for(int eq=0; eq<2; eq++){
                    ans+=dp[n-1][xd1][xd2][eq];
                }
            //}
            }
    }
    return ans;
}
 
int32_t main(){
    ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();
    //while(cin>>a) cout<<f(a)<<endl;
    cin>>a>>b;
    a--;
    cout<<f(b)-f(a);
}

• Subtask 1: 13.75 / 25
• Subtask 2: 75 / 75