Submission #563441

#	Time	Username	Problem	Language	Result	Execution time	Memory
563441		tht2005	Palindrome-Free Numbers (BOI13_numbers)	C++17	100 / 100	1 ms	464 KiB

numbers

#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

char a[20];
LL f[20][2][11][11];

LL calc(LL x) {
    sprintf(a, "%lld", x);
    int n = strlen(a);
    for(int i = 0; i <= n; ++i) {
        memset(f[i], 0, sizeof(f[i]));
    }
    f[0][0][10][10] = 1;
    for(int i = 0; i < n; ++i) {
        for(int t = 0; t < 2; ++t) {
            for(int j = 0; j < 11; ++j) {
                for(int k = 0; k < 11; ++k) {
                    LL ft = f[i][t][j][k];
                    if(ft == 0) continue;
                    if(k == 10) f[i + 1][1][10][10] += ft;
                    for(int c = (k == 10); t ? (c < 10) : (c <= a[i] - '0'); ++c) {
                        if(c == j || c == k) continue;
                        f[i + 1][t || (c < a[i] - '0')][k][c] += ft;
                    }
                }
            }
        }
    }
    LL res = 0;
    for(int i = 0; i < 11; ++i) {
        for(int j = 0; j < 11; ++j) {
            res += f[n][1][i][j];
        }
    }
    return res;
}

int main() {
    LL l, r;
    scanf("%lld %lld", &l, &r);
    printf("%lld", calc(r + 1) - calc(l) + (l == 0));
    return 0;
}

Compilation message (stderr)

numbers.cpp: In function 'int main()':
numbers.cpp:43:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |     scanf("%lld %lld", &l, &r);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~

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