結果

問題 No.6 使いものにならないハッシュ
コンテスト
ユーザー Ricky_pon
提出日時 2020-05-18 06:45:47
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 10 ms / 5,000 ms
コード長 2,269 bytes
コンパイル時間 3,018 ms
コンパイル使用メモリ 206,004 KB
最終ジャッジ日時 2025-01-10 12:49:41
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 32
権限があれば一括ダウンロードができます
コンパイルメッセージ
main.cpp: In function ‘int main()’:
main.cpp:75:10: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   75 |     scanf("%d%d", &K, &n);
      |     ~~~~~^~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:980,
                 from /usr/include/c++/13/cstdio:42,
                 from /usr/include/c++/13/ext/string_conversions.h:45,
                 from /usr/include/c++/13/bits/basic_string.h:4109,
                 from /usr/include/c++/13/string:54,
                 from /usr/include/c++/13/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:52,
                 from main.cpp:1:
In function ‘int printf(const char*, ...)’,
    inlined from ‘int main()’ at main.cpp:97:11:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:86:23: warning: ‘ans’ may be used uninitialized [-Wmaybe-uninitialized]
   86 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ());
      |          ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
main.cpp: In function ‘int main()’:
main.cpp:82:9: note: ‘ans’ was declared here
   82 |     int ans, len = 0;
      |         ^~~

ソースコード

diff # 

#include <bits/stdc++.h>
#define For(i, a, b) for(int (i)=(int)(a); (i)<(int)(b); ++(i))
#define rFor(i, a, b) for(int (i)=(int)(a)-1; (i)>=(int)(b); --(i))
#define rep(i, n) For((i), 0, (n))
#define rrep(i, n) rFor((i), (n), 0)
#define fi first
#define se second
using namespace std;
typedef long long lint;
typedef unsigned long long ulint;
typedef pair<int, int> pii;
typedef pair<lint, lint> pll;
template<class T> bool chmax(T &a, const T &b){if(a<b){a=b; return true;} return false;}
template<class T> bool chmin(T &a, const T &b){if(a>b){a=b; return true;} return false;}
template<class T> T div_floor(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>=0 ? a/b : (a+1)/b-1;
}
template<class T> T div_ceil(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>0 ? (a-1)/b+1 : a/b;
}

constexpr lint mod = 1e9+7;
constexpr lint INF = mod * mod;
constexpr int MAX = 200010;

vector<int> min_factor, prime;

void sieve(int n){
    min_factor.resize(n+1, 0);
    For(i, 2, n+1){
        if(min_factor[i] == 0){
            min_factor[i] = i;
            prime.push_back(i);
        }
        for(int x: prime){
            if(x*i > n || x > i) break;
            min_factor[x*i] = x;
        }
    }
}

vector<pii> prime_f(int n){
    vector<pii> ret;
    while(n > 1){
        if(ret.empty() || ret.rbegin()->fi != min_factor[n]){
            ret.emplace_back(min_factor[n], 1);
        }
        else ++ret.rbegin()->se;
        n /= min_factor[n];
    }
    return ret;
}

bool is_prime(int n){
    return min_factor[n] == n;
}

int dp[MAX];

int f(int n){
    if(dp[n]) return dp[n];
    if(0<=n && n<10) return dp[n] = n;
    int ret = 0;
    while(n){
        ret += n % 10;
        n /= 10;
    }
    return f(ret);
}

int main(){
    int K, n;
    scanf("%d%d", &K, &n);
    sieve(n);
    vector<int> p, h;
    For(i, K, n+1)if(is_prime(i)){
        p.push_back(i);
        h.push_back(f(i));
    }
    int ans, len = 0;
    for(int l=0; l<p.size();){
        int r = l;
        set<int> S;
        while(r < p.size() && S.find(h[r]) == S.end()){
            S.insert(h[r]);
            ++r;
        }
        if(len <= r-l){
            len = r-l;
            ans = p[l];
        }
        S.erase(h[l]);
        ++l;
    }
    printf("%d\n", ans);
}
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