Submission #1120805

#	Time	Username	Problem	Language	Result	Execution time	Memory
1120805		vjudge1	Palindrome-Free Numbers (BOI13_numbers)	C++17	85 / 100	5 ms	576 KiB

numbers

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long long
#define INF 1000000000
bool check(string a){
    bool can = 1;
    int n = a.size();
    for (int i = 0; i < n - 1; i++){
        if (a[i] == a[i + 1]) can = 0;
    }
    for (int i = 1; i < n - 1; i++){
        if (a[i - 1] == a[i + 1]) can = 0;
    }
    return can;
}
ll calc(string a, string b){
    while (a.size() < b.size()){
        a = "0" + a;
    }
    int n = b.size();
    vector<vector<vector<vector<ll>>>> dp(n + 1, vector<vector<vector<ll>>>(10, vector<vector<ll>>(10, vector<ll>(4, 0))));
    if (a[0] == b[0]){
        dp[0][a[0] - '0'][a[0] - '0'][3] = 1;
    }
    else{
        int st = a[0] - '0', en = b[0] - '0';
        for (int i = st + 1; i < en; i++){
            dp[0][i][i][0] = 1;
        }
        dp[0][st][st][1] = dp[0][en][en][2] = 1;
    }
    for (int i = 1; i < n; i++){
        int st = a[i] - '0', en = b[i] - '0';
        for (int j = 0; j < 10; j++){
            for (int k = 0; k < 10; k++){
                for (int l = 0; l < 4; l++){
                    for (int no = 0; no < 10; no++){
                        if (no == j || no == k) continue;
                        if (no < st && (l == 1 || l == 3)) continue;
                        if (no > en && (l == 2 || l == 3)) continue;
                        int ne = 0;
                        if (no == st && (l == 1 || l == 3)){
                            ne += 1;
                        }
                        if (no == en && (l == 2 || l == 3)){
                            ne += 2;
                        }
                        dp[i][k][no][ne] += dp[i - 1][j][k][l];
                    }
                }
            }
        }
    }
    ll ans = 0;
    for (int i = 0; i < 10; i++){
        for (int j = 0; j < 10; j++){
            for (int k = 0; k < 4; k++){
                ans += dp[n - 1][i][j][k];
            }
        }
    }
    return ans;
}
int main(){
    unsigned ll a, b, ans = 0;
    cin>>a>>b;
    if (b - a <= 100000){
        for (ll i = a; i <= b; i++){
            if (check(to_string(i))) ans++;
        }
    }
    else{
        string str1 = "0", str2 = "9";
        for (int i = 0; i < 20; i++){
            unsigned ll nu1 = stoull(str1), nu2 = stoull(str2);
            if (nu1 > b){
                break;
            }
            if (nu2 < a){
                str1 = "1" + str1, str2 = str2 + "9";
                continue;
            }
            ans += calc(to_string(max(nu1, a)), to_string(min(nu2, b)));
            str1 = "1" + str1, str2 = str2 + "9";
        }
    }
    cout<<ans;
}

Compilation message (stderr)

numbers.cpp: In function 'int main()':
numbers.cpp:69:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'long long unsigned int' [-Wsign-compare]
   69 |         for (ll i = a; i <= b; i++){
      |                        ~~^~~~

• Subtask 1: 25 / 25
• Subtask 2: 60 / 75