Submission #369279

#	Time	Username	Problem	Language	Result	Execution time	Memory
369279		Sparky_09	Palindrome-Free Numbers (BOI13_numbers)	C++17	100 / 100	1 ms	512 KiB

numbers

#include "bits/stdc++.h"
using namespace std;
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define trav(a, x) for(auto& a : x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<ll, ll> pii;
typedef vector<ll> vi;
typedef vector<pii> vpi;

int rd() {
	int result = 0;
	char ch;
	ch = getchar();
	while(ch < '0' || ch > '9') ch = getchar();
	result = ch-'0';
	while (true) {
		ch = getchar();
		if (ch < '0' || ch > '9') break;
		result = result*10 + (ch - '0');
	}
	return result;
}

template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

void usaco(string s){
  freopen((s+".in").c_str(), "r", stdin);
  freopen((s+".out").c_str(), "w", stdout);
}

int a[70], len;
ll x, y, f[70][11][11];

ll dfs(int now, int pre, int ppre, int st, int limit) {
    if(!now)
        return 1;

    if(!limit && ~f[now][pre][ppre])
        return f[now][pre][ppre];

    ll ret = 0;
    int Max = limit ? a[now] : 9;

    for(int i = 0; i <= Max; ++i){
        if(st && !i)
            ret += dfs(now - 1, 10, 10, st, limit && (i == Max));
        else if(i == ppre || i == pre)
            continue;
        else
            ret += dfs(now - 1, i, pre, 0, limit && (i == Max));
    }

    if(!limit && !st)
        f[now][pre][ppre] = ret;

    return ret;
}

ll work(ll x) {
    if(x < 0)
        return 0;

    len = 0;

    while(x)
        a[++len] = x % 10, x /= 10;

    memset(f, -1, sizeof(f));
    return dfs(len, 10, 10, 1, 1);
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);
#ifdef LOCAL_DEFINE
	freopen("input.txt", "r", stdin);
#endif
  cin >> x >> y;
  cout << work(y) - work(x-1) << '\n';
}

Compilation message (stderr)

numbers.cpp: In function 'void usaco(std::string)':
numbers.cpp:30:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   30 |   freopen((s+".in").c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
numbers.cpp:31:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   31 |   freopen((s+".out").c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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