제출 #77201

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
77201		Vinhspm	Palindrome-Free Numbers (BOI13_numbers)	C++14	72.50 / 100	3 ms	704 KiB

numbers

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

#define fi first
#define se second
#define FOR(a, b, c) for(int a=b;a <= c;++a)
#define pb push_back
#define int long long

const int N = 1e5 + 10;
const int mod = 1e9 + 7;
const int oo = 1e9;

int n;
int f[20][11][11][2];
void add(int &x, int y)  { x = (x + y); }
int solve(string maxn, int st) {
    memset(f, 0, sizeof f);
    f[0][0][0][0] = 1;
    FOR(i, 0, 17) FOR(las2, 0, 9) FOR(las1, 0, 9) {
        if(f[i][las2][las1][0]) {

            int h = maxn[i] - '0';
            FOR(t, 0, h)    if((i <= st) || (i == st + 1 && t != las1) || (t != las1 && t != las2))    {
                bool flag = 1;
                if(t == h) flag = false;
                add(f[i + 1][las1][t][flag], f[i][las2][las1][0]);
                //cout << f[i + 1][las1][t][flag] << ' ' << flag << '\n';
            }
        }
        if(f[i][las2][las1][1]) {
            //cout << i << ' ' << las2 << ' ' << las1 << ' ' << f[i][las2][las1][1] << '\n';
            FOR(t, 0, 9)    if((i <= st) || (i == st + 1 && t != las1) || (t != las1 && t != las2))    {
                add(f[i + 1][las1][t][1], f[i][las2][las1][1]);
            }
        }
    }
    // we need f[18][las1][las2][0]
    int sum = 0;
    FOR(i, 0, 9) FOR(j, 0, 9) add(sum, f[18][i][j][0]), add(sum, f[18][i][j][1]);
    return sum;
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    int l, r;   cin >> l >> r; l --;
    string a = "", b = "";
    while(l)    a = char(l % 10 + 48) + a, l /= 10;
    int sa = 18 - a.length();
    while(a.length() < 18) a = "0" + a;
    while(r)    b = char(r % 10 + 48) + b, r /= 10;
    int sb = 18 - b.length();
    while(b.length() < 18) b = "0" + b;
    //cout << b << ' ' << sb << ' ' << a << ' ' << sa << '\n';
    cout << solve(b, sb) - solve(a, sa);// :D
}

• Subtask 1: 12.5 / 25
• Subtask 2: 60 / 75